diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenProperty.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenProperty.java
index c3cbfe56925..ce456b5647d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenProperty.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/CodegenProperty.java
@@ -111,8 +111,8 @@ public class CodegenProperty implements Cloneable, IJsonSchemaValidationProperti
     /**
      * True if this property is an array of items or a map container.
      * See:
-     * - ModelUtils.isArraySchema()
-     * - ModelUtils.isMapSchema()
+     * - modelUtils.isArraySchema()
+     * - modelUtils.isMapSchema()
      */
     public boolean isContainer;
     public boolean isString;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
index 80b52aa37da..692c71fe925 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java
@@ -332,7 +332,7 @@ public class DefaultCodegen implements CodegenConfig {
         }
 
         if (additionalProperties.containsKey(CodegenConstants.GENERATE_ALIAS_AS_MODEL)) {
-            ModelUtils.setGenerateAliasAsModel(Boolean.valueOf(additionalProperties
+            modelUtils.setGenerateAliasAsModel(Boolean.valueOf(additionalProperties
                     .get(CodegenConstants.GENERATE_ALIAS_AS_MODEL).toString()));
         }
 
@@ -462,7 +462,7 @@ public class DefaultCodegen implements CodegenConfig {
         if (modelNameToSchemaCache == null) {
             // Create a cache to efficiently lookup schema based on model name.
             Map<String, Schema> m = new HashMap<String, Schema>();
-            ModelUtils.getSchemas(openAPI).forEach((key, schema) -> {
+            modelUtils.getSchemas().forEach((key, schema) -> {
                 m.put(toModelName(key), schema);
             });
             modelNameToSchemaCache = Collections.unmodifiableMap(m);
@@ -747,7 +747,21 @@ public class DefaultCodegen implements CodegenConfig {
         this.openAPI = openAPI;
         // Set global settings such that helper functions in ModelUtils can lookup the value
         // of the CLI option.
-        ModelUtils.setDisallowAdditionalPropertiesIfNotPresent(getDisallowAdditionalPropertiesIfNotPresent());
+        modelUtils.setDisallowAdditionalPropertiesIfNotPresent(getDisallowAdditionalPropertiesIfNotPresent());
+    }
+
+    /**
+     * Get the OpenAPI document.
+     */
+    public OpenAPI getOpenAPI() {
+        return this.openAPI;
+    }
+
+    /**
+     * Get the ModeUtils object.
+     */
+    public ModelUtils getModelUtils() {
+        return this.modelUtils;
     }
 
     // override with any special post-processing
@@ -789,18 +803,18 @@ public class DefaultCodegen implements CodegenConfig {
                     for (Map.Entry<PathItem.HttpMethod, Operation> op : e.getValue().readOperationsMap().entrySet()) {
                         String opId = getOrGenerateOperationId(op.getValue(), e.getKey(), op.getKey().toString());
                         // process request body
-                        RequestBody b = ModelUtils.getReferencedRequestBody(openAPI, op.getValue().getRequestBody());
+                        RequestBody b = modelUtils.getReferencedRequestBody(op.getValue().getRequestBody());
                         Schema requestSchema = null;
                         if (b != null) {
-                            requestSchema = ModelUtils.getSchemaFromRequestBody(b);
+                            requestSchema = modelUtils.getSchemaFromRequestBody(b);
                         }
                         if (requestSchema != null) {
                             schemas.put(opId, requestSchema);
                         }
                         // process all response bodies
                         for (Map.Entry<String, ApiResponse> ar : op.getValue().getResponses().entrySet()) {
-                            ApiResponse a = ModelUtils.getReferencedApiResponse(openAPI, ar.getValue());
-                            Schema responseSchema = ModelUtils.getSchemaFromResponse(a);
+                            ApiResponse a = modelUtils.getReferencedApiResponse(ar.getValue());
+                            Schema responseSchema = modelUtils.getSchemaFromResponse(a);
                             if (responseSchema != null) {
                                 schemas.put(opId + ar.getKey(), responseSchema);
                             }
@@ -828,7 +842,7 @@ public class DefaultCodegen implements CodegenConfig {
                 String n = toModelName(e.getKey());
                 Schema s = e.getValue();
                 String nOneOf = toModelName(n + "OneOf");
-                if (ModelUtils.isComposedSchema(s)) {
+                if (modelUtils.isComposedSchema(s)) {
                     if (e.getKey().contains("/")) {
                         // if this is property schema, we also need to generate the oneOf interface model
                         addOneOfNameExtension((ComposedSchema) s, nOneOf);
@@ -837,15 +851,15 @@ public class DefaultCodegen implements CodegenConfig {
                         // else this is a component schema, so we will just use that as the oneOf interface model
                         addOneOfNameExtension((ComposedSchema) s, n);
                     }
-                } else if (ModelUtils.isArraySchema(s)) {
+                } else if (modelUtils.isArraySchema(s)) {
                     Schema items = ((ArraySchema) s).getItems();
-                    if (ModelUtils.isComposedSchema(items)) {
+                    if (modelUtils.isComposedSchema(items)) {
                         addOneOfNameExtension((ComposedSchema) items, nOneOf);
                         addOneOfInterfaceModel((ComposedSchema) items, nOneOf, openAPI);
                     }
-                } else if (ModelUtils.isMapSchema(s)) {
+                } else if (modelUtils.isMapSchema(s)) {
                     Schema addProps = getAdditionalProperties(s);
-                    if (addProps != null && ModelUtils.isComposedSchema(addProps)) {
+                    if (addProps != null && modelUtils.isComposedSchema(addProps)) {
                         addOneOfNameExtension((ComposedSchema) addProps, nOneOf);
                         addOneOfInterfaceModel((ComposedSchema) addProps, nOneOf, openAPI);
                     }
@@ -1646,15 +1660,15 @@ public class DefaultCodegen implements CodegenConfig {
      * @return string presentation of the instantiation type of the property
      */
     public String toInstantiationType(Schema schema) {
-        if (ModelUtils.isMapSchema(schema)) {
+        if (modelUtils.isMapSchema(schema)) {
             Schema additionalProperties = getAdditionalProperties(schema);
             String inner = getSchemaType(additionalProperties);
             return instantiationTypes.get("map") + "<String, " + inner + ">";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             ArraySchema arraySchema = (ArraySchema) schema;
             String inner = getSchemaType(getSchemaItems(arraySchema));
             String parentType;
-            if (ModelUtils.isSet(schema)) {
+            if (modelUtils.isSet(schema)) {
                 parentType = "set";
             } else {
                 parentType = "array";
@@ -1750,7 +1764,7 @@ public class DefaultCodegen implements CodegenConfig {
         Content content = requestBody.getContent();
 
         if (content.size() > 1) {
-            // @see ModelUtils.getSchemaFromContent()
+            // @see modelUtils.getSchemaFromContent()
             once(LOGGER).warn("Multiple MediaTypes found, using only the first one");
         }
 
@@ -1831,19 +1845,19 @@ public class DefaultCodegen implements CodegenConfig {
         /*
          * Although all branches return null, this is left intentionally as examples for new contributors
          */
-        if (ModelUtils.isBooleanSchema(schema)) {
+        if (modelUtils.isBooleanSchema(schema)) {
             return "null";
-        } else if (ModelUtils.isDateSchema(schema)) {
+        } else if (modelUtils.isDateSchema(schema)) {
             return "null";
-        } else if (ModelUtils.isDateTimeSchema(schema)) {
+        } else if (modelUtils.isDateTimeSchema(schema)) {
             return "null";
-        } else if (ModelUtils.isNumberSchema(schema)) {
+        } else if (modelUtils.isNumberSchema(schema)) {
             return "null";
-        } else if (ModelUtils.isIntegerSchema(schema)) {
+        } else if (modelUtils.isIntegerSchema(schema)) {
             return "null";
-        } else if (ModelUtils.isStringSchema(schema)) {
+        } else if (modelUtils.isStringSchema(schema)) {
             return "null";
-        } else if (ModelUtils.isObjectSchema(schema)) {
+        } else if (modelUtils.isObjectSchema(schema)) {
             return "null";
         } else {
             return "null";
@@ -1874,7 +1888,7 @@ public class DefaultCodegen implements CodegenConfig {
         if (schema instanceof ComposedSchema) { // composed schema
             ComposedSchema cs = (ComposedSchema) schema;
             // Get the interfaces, i.e. the set of elements under 'allOf', 'anyOf' or 'oneOf'.
-            List<Schema> schemas = ModelUtils.getInterfaces(cs);
+            List<Schema> schemas = modelUtils.getInterfaces(cs);
 
             List<String> names = new ArrayList<>();
             // Build a list of the schema types under each interface.
@@ -1976,7 +1990,7 @@ public class DefaultCodegen implements CodegenConfig {
     }
 
     public Schema unaliasSchema(Schema schema, Map<String, String> usedImportMappings) {
-        return ModelUtils.unaliasSchema(this.openAPI, schema, usedImportMappings);
+        return modelUtils.unaliasSchema(schema, usedImportMappings);
     }
 
     /**
@@ -1990,7 +2004,7 @@ public class DefaultCodegen implements CodegenConfig {
 
         if (StringUtils.isNotBlank(unaliasSchema.get$ref())) { // reference to another definition/schema
             // get the schema/model name from $ref
-            String schemaName = ModelUtils.getSimpleRef(unaliasSchema.get$ref());
+            String schemaName = modelUtils.getSimpleRef(unaliasSchema.get$ref());
             if (StringUtils.isNotEmpty(schemaName)) {
                 if (importMapping.containsKey(schemaName)) {
                     return schemaName;
@@ -2018,55 +2032,55 @@ public class DefaultCodegen implements CodegenConfig {
     private String getPrimitiveType(Schema schema) {
         if (schema == null) {
             throw new RuntimeException("schema cannot be null in getPrimitiveType");
-        } else if (ModelUtils.isNullType(schema)) {
+        } else if (modelUtils.isNullType(schema)) {
             // The 'null' type is allowed in OAS 3.1 and above. It is not supported by OAS 3.0.x,
             // though this tooling supports it.
             return "null";
-        } else if (ModelUtils.isDecimalSchema(schema)) {
+        } else if (modelUtils.isDecimalSchema(schema)) {
             // special handle of type: string, format: number
             return "decimal";
-        } else if (ModelUtils.isByteArraySchema(schema)) {
+        } else if (modelUtils.isByteArraySchema(schema)) {
             return "ByteArray";
-        } else if (ModelUtils.isFileSchema(schema)) {
+        } else if (modelUtils.isFileSchema(schema)) {
             return "file";
-        } else if (ModelUtils.isBinarySchema(schema)) {
+        } else if (modelUtils.isBinarySchema(schema)) {
             return SchemaTypeUtil.BINARY_FORMAT;
-        } else if (ModelUtils.isBooleanSchema(schema)) {
+        } else if (modelUtils.isBooleanSchema(schema)) {
             return SchemaTypeUtil.BOOLEAN_TYPE;
-        } else if (ModelUtils.isDateSchema(schema)) {
+        } else if (modelUtils.isDateSchema(schema)) {
             return SchemaTypeUtil.DATE_FORMAT;
-        } else if (ModelUtils.isDateTimeSchema(schema)) {
+        } else if (modelUtils.isDateTimeSchema(schema)) {
             return "DateTime";
-        } else if (ModelUtils.isNumberSchema(schema)) {
+        } else if (modelUtils.isNumberSchema(schema)) {
             if (schema.getFormat() == null) { // no format defined
                 return "number";
-            } else if (ModelUtils.isFloatSchema(schema)) {
+            } else if (modelUtils.isFloatSchema(schema)) {
                 return SchemaTypeUtil.FLOAT_FORMAT;
-            } else if (ModelUtils.isDoubleSchema(schema)) {
+            } else if (modelUtils.isDoubleSchema(schema)) {
                 return SchemaTypeUtil.DOUBLE_FORMAT;
             } else {
                 LOGGER.warn("Unknown `format` {} detected for type `number`. Defaulting to `number`", schema.getFormat());
                 return "number";
             }
-        } else if (ModelUtils.isIntegerSchema(schema)) {
-            if (ModelUtils.isLongSchema(schema)) {
+        } else if (modelUtils.isIntegerSchema(schema)) {
+            if (modelUtils.isLongSchema(schema)) {
                 return "long";
             } else {
                 return schema.getType(); // integer
             }
-        } else if (ModelUtils.isMapSchema(schema)) {
+        } else if (modelUtils.isMapSchema(schema)) {
             return "map";
-        } else if (ModelUtils.isArraySchema(schema)) {
-            if (ModelUtils.isSet(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
+            if (modelUtils.isSet(schema)) {
                 return "set";
             } else {
                 return "array";
             }
-        } else if (ModelUtils.isUUIDSchema(schema)) {
+        } else if (modelUtils.isUUIDSchema(schema)) {
             return "UUID";
-        } else if (ModelUtils.isURISchema(schema)) {
+        } else if (modelUtils.isURISchema(schema)) {
             return "URI";
-        } else if (ModelUtils.isStringSchema(schema)) {
+        } else if (modelUtils.isStringSchema(schema)) {
             if (typeMapping.containsKey(schema.getFormat())) {
                 // If the format matches a typeMapping (supplied with the --typeMappings flag)
                 // then treat the format as a primitive type.
@@ -2075,13 +2089,13 @@ public class DefaultCodegen implements CodegenConfig {
                 return schema.getFormat();
             }
             return "string";
-        } else if (ModelUtils.isFreeFormObject(openAPI, schema)) {
+        } else if (modelUtils.isFreeFormObject(schema)) {
             // Note: the value of a free-form object cannot be an arbitrary type. Per OAS specification,
             // it must be a map of string to values.
             return "object";
         } else if (schema.getProperties() != null && !schema.getProperties().isEmpty()) { // having property implies it's a model
             return "object";
-        } else if (ModelUtils.isAnyTypeSchema(openAPI, schema)) {
+        } else if (modelUtils.isAnyTypeSchema(schema)) {
             return "AnyType";
         } else if (StringUtils.isNotEmpty(schema.getType())) {
             if (!importMapping.containsKey(schema.getType())) {
@@ -2243,7 +2257,7 @@ public class DefaultCodegen implements CodegenConfig {
      * @return Codegen Model object
      */
     public CodegenModel fromModel(String name, Schema schema) {
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         if (typeAliases == null) {
             // Only do this once during first call
             typeAliases = getAllAliases(allDefinitions);
@@ -2290,7 +2304,7 @@ public class DefaultCodegen implements CodegenConfig {
             m.xmlNamespace = schema.getXml().getNamespace();
             m.xmlName = schema.getXml().getName();
         }
-        if (ModelUtils.isAnyTypeSchema(openAPI, schema)) {
+        if (modelUtils.isAnyTypeSchema(schema)) {
             // The 'null' value is allowed when the OAS schema is 'any type'.
             // See https://github.com/OAI/OpenAPI-Specification/issues/1389
             if (Boolean.FALSE.equals(schema.getNullable())) {
@@ -2298,13 +2312,13 @@ public class DefaultCodegen implements CodegenConfig {
             }
             m.isNullable = true;
         }
-        if (ModelUtils.isArraySchema(schema)) {
+        if (modelUtils.isArraySchema(schema)) {
             m.isArray = true;
             CodegenProperty arrayProperty = fromProperty(name, schema);
             m.setItems(arrayProperty.items);
             m.arrayModelType = arrayProperty.complexType;
             addParentContainer(m, name, schema);
-            ModelUtils.syncValidationProperties(schema, m);
+            modelUtils.syncValidationProperties(schema, m);
         } else if (schema instanceof ComposedSchema) {
             final ComposedSchema composed = (ComposedSchema) schema;
             Map<String, Schema> properties = new LinkedHashMap<String, Schema>();
@@ -2322,8 +2336,8 @@ public class DefaultCodegen implements CodegenConfig {
             }
 
             // parent model
-            final String parentName = ModelUtils.getParentName(composed, allDefinitions);
-            final List<String> allParents = ModelUtils.getAllParentsName(composed, allDefinitions, false);
+            final String parentName = modelUtils.getParentName(composed, allDefinitions);
+            final List<String> allParents = modelUtils.getAllParentsName(composed, allDefinitions, false);
             final Schema parent = StringUtils.isBlank(parentName) || allDefinitions == null ? null : allDefinitions.get(parentName);
 
             // TODO revise the logic below to set dicriminator, xml attributes
@@ -2360,7 +2374,7 @@ public class DefaultCodegen implements CodegenConfig {
             }
 
             // interfaces (schemas defined in allOf, anyOf, oneOf)
-            List<Schema> interfaces = ModelUtils.getInterfaces(composed);
+            List<Schema> interfaces = modelUtils.getInterfaces(composed);
             if (!interfaces.isEmpty()) {
                 // m.interfaces is for backward compatibility
                 if (m.interfaces == null)
@@ -2395,7 +2409,7 @@ public class DefaultCodegen implements CodegenConfig {
 
                     // the rest of the section is for model
                     Schema refSchema = null;
-                    String ref = ModelUtils.getSimpleRef(interfaceSchema.get$ref());
+                    String ref = modelUtils.getSimpleRef(interfaceSchema.get$ref());
                     if (allDefinitions != null) {
                         refSchema = allDefinitions.get(ref);
                     }
@@ -2492,50 +2506,50 @@ public class DefaultCodegen implements CodegenConfig {
                 m.allowableValues = new HashMap<String, Object>();
                 m.allowableValues.put("values", schema.getEnum());
             }
-            if (ModelUtils.isMapSchema(schema)) {
+            if (modelUtils.isMapSchema(schema)) {
                 addAdditionPropertiesToCodeGenModel(m, schema);
                 m.isMap = true;
-            } else if (ModelUtils.isIntegerSchema(schema)) { // integer type
+            } else if (modelUtils.isIntegerSchema(schema)) { // integer type
                 // NOTE: Integral schemas as CodegenModel is a rare use case and may be removed at a later date.
                 // Sync of properties is done for consistency with other data types like CodegenParameter/CodegenProperty.
-                ModelUtils.syncValidationProperties(schema, m);
+                modelUtils.syncValidationProperties(schema, m);
 
                 m.isNumeric = Boolean.TRUE;
-                if (ModelUtils.isLongSchema(schema)) { // int64/long format
+                if (modelUtils.isLongSchema(schema)) { // int64/long format
                     m.isLong = Boolean.TRUE;
                 } else { // int32 format
                     m.isInteger = Boolean.TRUE;
                 }
-            } else if (ModelUtils.isDateTimeSchema(schema)) {
+            } else if (modelUtils.isDateTimeSchema(schema)) {
                 // NOTE: DateTime schemas as CodegenModel is a rare use case and may be removed at a later date.
                 // Sync of properties is done for consistency with other data types like CodegenParameter/CodegenProperty.
-                ModelUtils.syncValidationProperties(schema, m);
+                modelUtils.syncValidationProperties(schema, m);
                 m.isDateTime = Boolean.TRUE;
-            } else if (ModelUtils.isDateSchema(schema)) {
+            } else if (modelUtils.isDateSchema(schema)) {
                 // NOTE: Date schemas as CodegenModel is a rare use case and may be removed at a later date.
                 // Sync of properties is done for consistency with other data types like CodegenParameter/CodegenProperty.
-                ModelUtils.syncValidationProperties(schema, m);
+                modelUtils.syncValidationProperties(schema, m);
                 m.isDate = Boolean.TRUE;
-            } else if (ModelUtils.isStringSchema(schema)) {
+            } else if (modelUtils.isStringSchema(schema)) {
                 // NOTE: String schemas as CodegenModel is a rare use case and may be removed at a later date.
                 // Sync of properties is done for consistency with other data types like CodegenParameter/CodegenProperty.
-                ModelUtils.syncValidationProperties(schema, m);
+                modelUtils.syncValidationProperties(schema, m);
                 m.isString = Boolean.TRUE;
-            } else if (ModelUtils.isNumberSchema(schema)) {
+            } else if (modelUtils.isNumberSchema(schema)) {
                 // NOTE: Number schemas as CodegenModel is a rare use case and may be removed at a later date.
                 // Sync of properties is done for consistency with other data types like CodegenParameter/CodegenProperty.
-                ModelUtils.syncValidationProperties(schema, m);
+                modelUtils.syncValidationProperties(schema, m);
                 m.isNumeric = Boolean.TRUE;
-                if (ModelUtils.isFloatSchema(schema)) { // float
+                if (modelUtils.isFloatSchema(schema)) { // float
                     m.isFloat = Boolean.TRUE;
-                } else if (ModelUtils.isDoubleSchema(schema)) { // double
+                } else if (modelUtils.isDoubleSchema(schema)) { // double
                     m.isDouble = Boolean.TRUE;
                 } else { // type is number and without format
                     m.isNumber = Boolean.TRUE;
                 }
-            } else if (ModelUtils.isFreeFormObject(openAPI, schema)) {
+            } else if (modelUtils.isFreeFormObject(schema)) {
                 addAdditionPropertiesToCodeGenModel(m, schema);
-                ModelUtils.syncValidationProperties(schema, m);
+                modelUtils.syncValidationProperties(schema, m);
             }
 
             if (Boolean.TRUE.equals(schema.getNullable())) {
@@ -2626,11 +2640,11 @@ public class DefaultCodegen implements CodegenConfig {
      * @param discPropName       The String that is the discriminator propertyName in the schema
      */
     private CodegenProperty discriminatorFound(String composedSchemaName, Schema sc, String discPropName, OpenAPI openAPI) {
-        Schema refSchema = ModelUtils.getReferencedSchema(openAPI, sc);
+        Schema refSchema = modelUtils.getReferencedSchema(sc);
         if (refSchema.getProperties() != null && refSchema.getProperties().get(discPropName) != null) {
             Schema discSchema = (Schema) refSchema.getProperties().get(discPropName);
             CodegenProperty cp = new CodegenProperty();
-            if (ModelUtils.isStringSchema(discSchema)) {
+            if (modelUtils.isStringSchema(discSchema)) {
                 cp.isString = true;
             }
             cp.setRequired(false);
@@ -2639,7 +2653,7 @@ public class DefaultCodegen implements CodegenConfig {
             }
             return cp;
         }
-        if (ModelUtils.isComposedSchema(refSchema)) {
+        if (modelUtils.isComposedSchema(refSchema)) {
             ComposedSchema composedSchema = (ComposedSchema) refSchema;
             if (composedSchema.getAllOf() != null) {
                 // If our discriminator is in one of the allOf schemas break when we find it
@@ -2654,7 +2668,7 @@ public class DefaultCodegen implements CodegenConfig {
                 // All oneOf definitions must contain the discriminator
                 CodegenProperty cp = new CodegenProperty();
                 for (Schema oneOf : composedSchema.getOneOf()) {
-                    String modelName = ModelUtils.getSimpleRef(oneOf.get$ref());
+                    String modelName = modelUtils.getSimpleRef(oneOf.get$ref());
                     CodegenProperty thisCp = discriminatorFound(composedSchemaName, oneOf, discPropName, openAPI);
                     if (thisCp == null) {
                         throw new RuntimeException("'" + composedSchemaName + "' defines discriminator '" + discPropName + "', but the referenced OneOf schema '" + modelName + "' is missing " + discPropName);
@@ -2673,7 +2687,7 @@ public class DefaultCodegen implements CodegenConfig {
                 // All anyOf definitions must contain the discriminator because a min of one must be selected
                 CodegenProperty cp = new CodegenProperty();
                 for (Schema anyOf : composedSchema.getAnyOf()) {
-                    String modelName = ModelUtils.getSimpleRef(anyOf.get$ref());
+                    String modelName = modelUtils.getSimpleRef(anyOf.get$ref());
                     CodegenProperty thisCp = discriminatorFound(composedSchemaName, anyOf, discPropName, openAPI);
                     if (thisCp == null) {
                         throw new RuntimeException("'" + composedSchemaName + "' defines discriminator '" + discPropName + "', but the referenced AnyOf schema '" + modelName + "' is missing " + discPropName);
@@ -2701,7 +2715,7 @@ public class DefaultCodegen implements CodegenConfig {
      * @param sc The Schema that may contain the discriminator
      */
     private Discriminator recursiveGetDiscriminator(Schema sc, OpenAPI openAPI) {
-        Schema refSchema = ModelUtils.getReferencedSchema(openAPI, sc);
+        Schema refSchema = modelUtils.getReferencedSchema(sc);
         Discriminator foundDisc = refSchema.getDiscriminator();
         if (foundDisc != null) {
             return foundDisc;
@@ -2711,7 +2725,7 @@ public class DefaultCodegen implements CodegenConfig {
             return null;
         }
         Discriminator disc = new Discriminator();
-        if (ModelUtils.isComposedSchema(refSchema)) {
+        if (modelUtils.isComposedSchema(refSchema)) {
             ComposedSchema composedSchema = (ComposedSchema) refSchema;
             if (composedSchema.getAllOf() != null) {
                 // If our discriminator is in one of the allOf schemas break when we find it
@@ -2730,7 +2744,7 @@ public class DefaultCodegen implements CodegenConfig {
                 Integer hasNullTypeCnt = 0;
                 Set<String> discriminatorsPropNames = new HashSet<>();
                 for (Schema oneOf : composedSchema.getOneOf()) {
-                    if (ModelUtils.isNullType(oneOf)) {
+                    if (modelUtils.isNullType(oneOf)) {
                         // The null type does not have a discriminator. Skip.
                         hasNullTypeCnt++;
                         continue;
@@ -2759,7 +2773,7 @@ public class DefaultCodegen implements CodegenConfig {
                 Integer hasNullTypeCnt = 0;
                 Set<String> discriminatorsPropNames = new HashSet<>();
                 for  (Schema anyOf : composedSchema.getAnyOf()) {
-                    if (ModelUtils.isNullType(anyOf)) {
+                    if (modelUtils.isNullType(anyOf)) {
                         // The null type does not have a discriminator. Skip.
                         hasNullTypeCnt++;
                         continue;
@@ -2810,7 +2824,7 @@ public class DefaultCodegen implements CodegenConfig {
                 continue;
             }
             for (Schema sc : schemaList) {
-                if (ModelUtils.isNullType(sc)) {
+                if (modelUtils.isNullType(sc)) {
                     continue;
                 }
                 String ref = sc.get$ref();
@@ -2824,7 +2838,7 @@ public class DefaultCodegen implements CodegenConfig {
                     throw new RuntimeException("Invalid inline schema defined in oneOf/anyOf in '" + composedSchemaName + "'. Per the OpenApi spec, for this case when a composed schema defines a discriminator, the oneOf/anyOf schemas must use $ref. Change this inline definition to a $ref definition");
                 }
                 CodegenProperty df = discriminatorFound(composedSchemaName, sc, discPropName, openAPI);
-                String modelName = ModelUtils.getSimpleRef(ref);
+                String modelName = modelUtils.getSimpleRef(ref);
                 if (df == null || !df.isString || df.required != true) {
                     String msgSuffix = "";
                     if (df == null) {
@@ -2845,7 +2859,7 @@ public class DefaultCodegen implements CodegenConfig {
                 }
                 MappedModel mm = new MappedModel(modelName, toModelName(modelName));
                 descendentSchemas.add(mm);
-                Schema cs = ModelUtils.getSchema(openAPI, modelName);
+                Schema cs = modelUtils.getSchema(modelName);
                 Map<String, Object> vendorExtensions = cs.getExtensions();
                 if (vendorExtensions != null && !vendorExtensions.isEmpty() && vendorExtensions.containsKey("x-discriminator-value")) {
                     String xDiscriminatorValue = (String) vendorExtensions.get("x-discriminator-value");
@@ -2861,7 +2875,7 @@ public class DefaultCodegen implements CodegenConfig {
     protected List<MappedModel> getAllOfDescendants(String thisSchemaName, OpenAPI openAPI) {
         ArrayList<String> queue = new ArrayList();
         List<MappedModel> descendentSchemas = new ArrayList();
-        Map<String, Schema> schemas = ModelUtils.getSchemas(openAPI);
+        Map<String, Schema> schemas = modelUtils.getSchemas();
         String currentSchemaName = thisSchemaName;
         Set<String> keys = schemas.keySet();
 
@@ -2873,7 +2887,7 @@ public class DefaultCodegen implements CodegenConfig {
                     continue;
                 }
                 Schema child = schemas.get(childName);
-                if (ModelUtils.isComposedSchema(child)) {
+                if (modelUtils.isComposedSchema(child)) {
                     ComposedSchema composedChild = (ComposedSchema) child;
                     List<Schema> parents = composedChild.getAllOf();
                     if (parents != null) {
@@ -2885,7 +2899,7 @@ public class DefaultCodegen implements CodegenConfig {
                                 // we hit this use case when an allOf composed schema contains an inline schema
                                 continue;
                             }
-                            String parentName = ModelUtils.getSimpleRef(ref);
+                            String parentName = modelUtils.getSimpleRef(ref);
                             if (parentName != null && parentName.equals(currentSchemaName)) {
                                 if (queue.contains(childName) || descendentSchemas.stream().anyMatch(i -> childName.equals(i.getMappingName()))) {
                                     throw new RuntimeException("Stack overflow hit when looking for " + thisSchemaName + " an infinite loop starting and ending at " + childName + " was seen");
@@ -2931,7 +2945,7 @@ public class DefaultCodegen implements CodegenConfig {
         if (sourceDiscriminator.getMapping() != null && !sourceDiscriminator.getMapping().isEmpty()) {
             for (Entry<String, String> e : sourceDiscriminator.getMapping().entrySet()) {
                 String nameOrRef = e.getValue();
-                String name = nameOrRef.indexOf('/') >= 0 ? ModelUtils.getSimpleRef(nameOrRef) : nameOrRef;
+                String name = nameOrRef.indexOf('/') >= 0 ? modelUtils.getSimpleRef(nameOrRef) : nameOrRef;
                 String modelName = toModelName(name);
                 uniqueDescendants.add(new MappedModel(e.getKey(), modelName));
             }
@@ -2957,7 +2971,7 @@ public class DefaultCodegen implements CodegenConfig {
             }
         }
         // if there are composed oneOf/anyOf schemas, add them to this discriminator
-        if (ModelUtils.isComposedSchema(schema) && !this.getLegacyDiscriminatorBehavior()) {
+        if (modelUtils.isComposedSchema(schema) && !this.getLegacyDiscriminatorBehavior()) {
             List<MappedModel> otherDescendants = getOneOfAnyOfDescendants(schemaName, discPropName, (ComposedSchema) schema, openAPI);
             for (MappedModel otherDescendant : otherDescendants) {
                 if (!uniqueDescendants.contains(otherDescendant)) {
@@ -3020,7 +3034,7 @@ public class DefaultCodegen implements CodegenConfig {
         }
 
         if (StringUtils.isNotBlank(schema.get$ref())) {
-            Schema interfaceSchema = ModelUtils.getReferencedSchema(this.openAPI, schema);
+            Schema interfaceSchema = modelUtils.getReferencedSchema(schema);
             addProperties(properties, required, interfaceSchema);
             return;
         }
@@ -3075,7 +3089,7 @@ public class DefaultCodegen implements CodegenConfig {
 
         CodegenProperty property = CodegenModelFactory.newInstance(CodegenModelType.PROPERTY);
 
-        ModelUtils.syncValidationProperties(p, property);
+        modelUtils.syncValidationProperties(p, property);
 
         property.name = toVarName(name);
         property.baseName = name;
@@ -3102,9 +3116,9 @@ public class DefaultCodegen implements CodegenConfig {
             // Since $ref should be replaced with the model it refers
             // to, $ref'ing a model with 'deprecated' set should cause
             // the property to reflect the model's 'deprecated' value.
-            String ref = ModelUtils.getSimpleRef(p.get$ref());
+            String ref = modelUtils.getSimpleRef(p.get$ref());
             if (ref != null) {
-                Schema referencedSchema = ModelUtils.getSchemas(this.openAPI).get(ref);
+                Schema referencedSchema = modelUtils.getSchemas().get(ref);
                 if (referencedSchema != null && referencedSchema.getDeprecated() != null) {
                     property.deprecated = referencedSchema.getDeprecated();
                 }
@@ -3133,9 +3147,9 @@ public class DefaultCodegen implements CodegenConfig {
         }
 
         String type = getSchemaType(p);
-        if (ModelUtils.isIntegerSchema(p)) { // integer type
+        if (modelUtils.isIntegerSchema(p)) { // integer type
             property.isNumeric = Boolean.TRUE;
-            if (ModelUtils.isLongSchema(p)) { // int64/long format
+            if (modelUtils.isLongSchema(p)) { // int64/long format
                 property.isLong = Boolean.TRUE;
             } else { // int32 format
                 property.isInteger = Boolean.TRUE;
@@ -3162,17 +3176,17 @@ public class DefaultCodegen implements CodegenConfig {
             if (property.minimum != null || property.maximum != null || p.getMultipleOf() != null)
                 property.hasValidation = true;
 
-        } else if (ModelUtils.isBooleanSchema(p)) { // boolean type
+        } else if (modelUtils.isBooleanSchema(p)) { // boolean type
             property.isBoolean = true;
             property.getter = toBooleanGetter(name);
-        } else if (ModelUtils.isDateSchema(p)) { // date format
+        } else if (modelUtils.isDateSchema(p)) { // date format
             property.isString = false; // for backward compatibility with 2.x
             property.isDate = true;
 
-        } else if (ModelUtils.isDateTimeSchema(p)) { // date-time format
+        } else if (modelUtils.isDateTimeSchema(p)) { // date-time format
             property.isString = false; // for backward compatibility with 2.x
             property.isDateTime = true;
-        } else if (ModelUtils.isDecimalSchema(p)) { // type: string, format: number
+        } else if (modelUtils.isDecimalSchema(p)) { // type: string, format: number
             property.isDecimal = true;
             if (p.getMinimum() != null) {
                 property.minimum = String.valueOf(p.getMinimum());
@@ -3195,22 +3209,22 @@ public class DefaultCodegen implements CodegenConfig {
             if (property.minimum != null || property.maximum != null || p.getMultipleOf() != null) {
                 property.hasValidation = true;
             }
-        } else if (ModelUtils.isStringSchema(p)) {
-            if (ModelUtils.isByteArraySchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
+            if (modelUtils.isByteArraySchema(p)) {
                 property.isByteArray = true;
-            } else if (ModelUtils.isBinarySchema(p)) {
+            } else if (modelUtils.isBinarySchema(p)) {
                 property.isBinary = true;
                 property.isFile = true; // file = binary in OAS3
-            } else if (ModelUtils.isFileSchema(p)) {
+            } else if (modelUtils.isFileSchema(p)) {
                 property.isFile = true;
-            } else if (ModelUtils.isUUIDSchema(p)) {
+            } else if (modelUtils.isUUIDSchema(p)) {
                 // keep isString to true to make it backward compatible
                 property.isString = true;
                 property.isUuid = true;
-            } else if (ModelUtils.isURISchema(p)) {
+            } else if (modelUtils.isURISchema(p)) {
                 property.isString = true; // for backward compatibility
                 property.isUri = true;
-            } else if (ModelUtils.isEmailSchema(p)) {
+            } else if (modelUtils.isEmailSchema(p)) {
                 property.isString = true;
                 property.isEmail = true;
             } else {
@@ -3225,11 +3239,11 @@ public class DefaultCodegen implements CodegenConfig {
             if (property.pattern != null || property.minLength != null || property.maxLength != null)
                 property.hasValidation = true;
 
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             property.isNumeric = Boolean.TRUE;
-            if (ModelUtils.isFloatSchema(p)) { // float
+            if (modelUtils.isFloatSchema(p)) { // float
                 property.isFloat = Boolean.TRUE;
-            } else if (ModelUtils.isDoubleSchema(p)) { // double
+            } else if (modelUtils.isDoubleSchema(p)) { // double
                 property.isDouble = Boolean.TRUE;
             } else { // type is number and without format
                 property.isNumber = Boolean.TRUE;
@@ -3257,9 +3271,9 @@ public class DefaultCodegen implements CodegenConfig {
                 property.hasValidation = true;
             }
 
-        } else if (ModelUtils.isFreeFormObject(openAPI, p)) {
+        } else if (modelUtils.isFreeFormObject(p)) {
             property.isFreeFormObject = true;
-        } else if (ModelUtils.isAnyTypeSchema(openAPI, p)) {
+        } else if (modelUtils.isAnyTypeSchema(p)) {
             // The 'null' value is allowed when the OAS schema is 'any type'.
             // See https://github.com/OAI/OpenAPI-Specification/issues/1389
             if (Boolean.FALSE.equals(p.getNullable())) {
@@ -3267,11 +3281,11 @@ public class DefaultCodegen implements CodegenConfig {
             }
             property.isNullable = true;
             property.isAnyType = true;
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             // default to string if inner item is undefined
             ArraySchema arraySchema = (ArraySchema) p;
             Schema innerSchema = unaliasSchema(getSchemaItems(arraySchema), importMapping);
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema innerSchema = unaliasSchema(getAdditionalProperties(p), importMapping);
             if (innerSchema == null) {
                 LOGGER.error("Undefined map inner type for `{}`. Default to String.", p.getName());
@@ -3296,7 +3310,7 @@ public class DefaultCodegen implements CodegenConfig {
             }
         }
 
-        Schema referencedSchema = ModelUtils.getReferencedSchema(this.openAPI, p);
+        Schema referencedSchema = modelUtils.getReferencedSchema(p);
 
         //Referenced enum case:
         if (referencedSchema.getEnum() != null && !referencedSchema.getEnum().isEmpty()) {
@@ -3325,10 +3339,10 @@ public class DefaultCodegen implements CodegenConfig {
             property.datatypeWithEnum = property.dataType;
         }
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             property.isContainer = true;
             property.isArray = true;
-            if (ModelUtils.isSet(p)) {
+            if (modelUtils.isSet(p)) {
                 property.containerType = "set";
             } else {
                 property.containerType = "array";
@@ -3355,7 +3369,7 @@ public class DefaultCodegen implements CodegenConfig {
             Schema innerSchema = unaliasSchema(getSchemaItems(arraySchema), importMapping);
             CodegenProperty cp = fromProperty(itemName, innerSchema);
             updatePropertyForArray(property, cp);
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             property.isContainer = true;
             property.isMap = true;
             property.containerType = "map";
@@ -3372,13 +3386,13 @@ public class DefaultCodegen implements CodegenConfig {
             }
             CodegenProperty cp = fromProperty("inner", innerSchema);
             updatePropertyForMap(property, cp);
-        } else if (ModelUtils.isFreeFormObject(openAPI, p)) {
+        } else if (modelUtils.isFreeFormObject(p)) {
             property.isFreeFormObject = true;
             property.baseType = getSchemaType(p);
             if (languageSpecificPrimitives.contains(property.dataType)) {
                 property.isPrimitiveType = true;
             }
-        } else if (ModelUtils.isAnyTypeSchema(openAPI, p)) {
+        } else if (modelUtils.isAnyTypeSchema(p)) {
             property.isAnyType = true;
             property.baseType = getSchemaType(p);
             if (languageSpecificPrimitives.contains(property.dataType)) {
@@ -3386,8 +3400,8 @@ public class DefaultCodegen implements CodegenConfig {
             }
         } else { // model
             setNonArrayMapProperty(property, type);
-            Schema refOrCurrent = ModelUtils.getReferencedSchema(this.openAPI, p);
-            property.isModel = (ModelUtils.isComposedSchema(refOrCurrent) || ModelUtils.isObjectSchema(refOrCurrent)) && ModelUtils.isModel(refOrCurrent);
+            Schema refOrCurrent = modelUtils.getReferencedSchema(p);
+            property.isModel = (modelUtils.isComposedSchema(refOrCurrent) || modelUtils.isObjectSchema(refOrCurrent)) && modelUtils.isModel(refOrCurrent);
         }
 
         addVarsRequiredVarsAdditionaProps(p, property);
@@ -3606,16 +3620,16 @@ public class DefaultCodegen implements CodegenConfig {
                                         CodegenOperation op,
                                         ApiResponse methodResponse,
                                         Map<String, String> importMappings) {
-        Schema responseSchema = unaliasSchema(ModelUtils.getSchemaFromResponse(methodResponse), importMapping);
+        Schema responseSchema = unaliasSchema(modelUtils.getSchemaFromResponse(methodResponse), importMapping);
 
         if (responseSchema != null) {
             CodegenProperty cm = fromProperty("response", responseSchema);
 
-            if (ModelUtils.isArraySchema(responseSchema)) {
+            if (modelUtils.isArraySchema(responseSchema)) {
                 ArraySchema as = (ArraySchema) responseSchema;
                 CodegenProperty innerProperty = fromProperty("response", getSchemaItems(as));
                 op.returnBaseType = innerProperty.baseType;
-            } else if (ModelUtils.isMapSchema(responseSchema)) {
+            } else if (modelUtils.isMapSchema(responseSchema)) {
                 CodegenProperty innerProperty = fromProperty("response", getAdditionalProperties(responseSchema));
                 op.returnBaseType = innerProperty.baseType;
             } else {
@@ -3633,7 +3647,7 @@ public class DefaultCodegen implements CodegenConfig {
                     exampleStatusCode = key;
                 }
             }
-            op.examples = new ExampleGenerator(schemas, this.openAPI).generateFromResponseSchema(exampleStatusCode, responseSchema, getProducesInfo(this.openAPI, operation));
+            op.examples = new ExampleGenerator(schemas, this.openAPI).generateFromResponseSchema(exampleStatusCode, responseSchema, getProducesInfo(operation));
             op.defaultResponse = toDefaultValue(responseSchema);
             op.returnType = cm.dataType;
             op.returnFormat = cm.dataFormat;
@@ -3687,7 +3701,7 @@ public class DefaultCodegen implements CodegenConfig {
         if (operation == null)
             throw new RuntimeException("operation cannot be null in fromOperation");
 
-        Map<String, Schema> schemas = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> schemas = modelUtils.getSchemas();
         CodegenOperation op = CodegenModelFactory.newInstance(CodegenModelType.OPERATION);
         Set<String> imports = new HashSet<String>();
         if (operation.getExtensions() != null && !operation.getExtensions().isEmpty()) {
@@ -3816,7 +3830,7 @@ public class DefaultCodegen implements CodegenConfig {
                 }
             } else {
                 // process body parameter
-                requestBody = ModelUtils.getReferencedRequestBody(this.openAPI, requestBody);
+                requestBody = modelUtils.getReferencedRequestBody(requestBody);
 
                 String bodyParameterName = "";
                 if (op.vendorExtensions != null && op.vendorExtensions.containsKey("x-codegen-request-body-name")) {
@@ -3834,14 +3848,14 @@ public class DefaultCodegen implements CodegenConfig {
 
                 // add example
                 if (schemas != null) {
-                    op.requestBodyExamples = new ExampleGenerator(schemas, this.openAPI).generate(null, new ArrayList<String>(getConsumesInfo(this.openAPI, operation)), bodyParam.baseType);
+                    op.requestBodyExamples = new ExampleGenerator(schemas, this.openAPI).generate(null, new ArrayList<String>(getConsumesInfo(operation)), bodyParam.baseType);
                 }
             }
         }
 
         if (parameters != null) {
             for (Parameter param : parameters) {
-                param = ModelUtils.getReferencedParameter(this.openAPI, param);
+                param = modelUtils.getReferencedParameter(param);
 
                 CodegenParameter p = fromParameter(param, imports);
 
@@ -3988,7 +4002,7 @@ public class DefaultCodegen implements CodegenConfig {
                 contentSchema = mt.getSchema();
             }
             if (contentSchema != null) {
-                ModelUtils.syncValidationProperties(contentSchema, r);
+                modelUtils.syncValidationProperties(contentSchema, r);
             }
         }
 
@@ -4020,9 +4034,9 @@ public class DefaultCodegen implements CodegenConfig {
 
         Schema responseSchema;
         if (this.openAPI != null && this.openAPI.getComponents() != null) {
-            responseSchema = unaliasSchema(ModelUtils.getSchemaFromResponse(response), importMapping);
+            responseSchema = unaliasSchema(modelUtils.getSchemaFromResponse(response), importMapping);
         } else { // no model/alias defined
-            responseSchema = ModelUtils.getSchemaFromResponse(response);
+            responseSchema = modelUtils.getSchemaFromResponse(response);
         }
         r.schema = responseSchema;
         if (responseSchema != null && responseSchema.getPattern() != null) {
@@ -4044,7 +4058,7 @@ public class DefaultCodegen implements CodegenConfig {
             Map<String, Schema> allSchemas = null;
             CodegenProperty cp = fromProperty("response", responseSchema);
 
-            if (ModelUtils.isArraySchema(responseSchema)) {
+            if (modelUtils.isArraySchema(responseSchema)) {
                 ArraySchema as = (ArraySchema) responseSchema;
                 CodegenProperty items = fromProperty("response", getSchemaItems(as));
                 r.setItems(items);
@@ -4223,7 +4237,7 @@ public class DefaultCodegen implements CodegenConfig {
                 contentSchema = mt.getSchema();
             }
             if (contentSchema != null) {
-                ModelUtils.syncValidationProperties(contentSchema, codegenParameter);
+                modelUtils.syncValidationProperties(contentSchema, codegenParameter);
             }
         }
 
@@ -4283,7 +4297,7 @@ public class DefaultCodegen implements CodegenConfig {
 
             // TODO revise collectionFormat
             String collectionFormat = null;
-            if (ModelUtils.isArraySchema(parameterSchema)) { // for array parameter
+            if (modelUtils.isArraySchema(parameterSchema)) { // for array parameter
                 final ArraySchema arraySchema = (ArraySchema) parameterSchema;
                 Schema inner = getSchemaItems(arraySchema);
 
@@ -4303,7 +4317,7 @@ public class DefaultCodegen implements CodegenConfig {
                     codegenProperty = codegenProperty.items;
                 }
 
-            } else if (ModelUtils.isMapSchema(parameterSchema)) { // for map parameter
+            } else if (modelUtils.isMapSchema(parameterSchema)) { // for map parameter
                 CodegenProperty codegenProperty = fromProperty("inner", getAdditionalProperties(parameterSchema));
                 codegenParameter.items = codegenProperty;
                 codegenParameter.mostInnerItems = codegenProperty.mostInnerItems;
@@ -4342,10 +4356,10 @@ public class DefaultCodegen implements CodegenConfig {
             } else {
                 codegenParameter.dataType = codegenProperty.dataType;
             }
-            if (ModelUtils.isObjectSchema(parameterSchema)) {
+            if (modelUtils.isObjectSchema(parameterSchema)) {
                 codegenProperty.complexType = codegenParameter.dataType;
             }
-            if (ModelUtils.isSet(parameterSchema)) {
+            if (modelUtils.isSet(parameterSchema)) {
                 imports.add(codegenProperty.baseType);
             }
             codegenParameter.dataFormat = codegenProperty.dataFormat;
@@ -4382,7 +4396,7 @@ public class DefaultCodegen implements CodegenConfig {
 
             // validation
             // handle maximum, minimum properly for int/long by removing the trailing ".0"
-            if (ModelUtils.isIntegerSchema(parameterSchema)) {
+            if (modelUtils.isIntegerSchema(parameterSchema)) {
                 codegenParameter.maximum = parameterSchema.getMaximum() == null ? null : String.valueOf(parameterSchema.getMaximum().longValue());
                 codegenParameter.minimum = parameterSchema.getMinimum() == null ? null : String.valueOf(parameterSchema.getMinimum().longValue());
             } else {
@@ -4451,13 +4465,13 @@ public class DefaultCodegen implements CodegenConfig {
      */
     protected String getParameterDataType(Parameter parameter, Schema schema) {
         if (parameter.get$ref() != null) {
-            String refName = ModelUtils.getSimpleRef(parameter.get$ref());
+            String refName = modelUtils.getSimpleRef(parameter.get$ref());
             return toModelName(refName);
         }
         return null;
     }
 
-    // TODO revise below as it should be replaced by ModelUtils.isByteArraySchema(parameterSchema)
+    // TODO revise below as it should be replaced by modelUtils.isByteArraySchema(parameterSchema)
     public boolean isDataTypeBinary(String dataType) {
         if (dataType != null) {
             return dataType.toLowerCase(Locale.ROOT).startsWith("byte");
@@ -4466,7 +4480,7 @@ public class DefaultCodegen implements CodegenConfig {
         }
     }
 
-    // TODO revise below as it should be replaced by ModelUtils.isFileSchema(parameterSchema)
+    // TODO revise below as it should be replaced by modelUtils.isFileSchema(parameterSchema)
     public boolean isDataTypeFile(String dataType) {
         if (dataType != null) {
             return dataType.toLowerCase(Locale.ROOT).equals("file");
@@ -4671,7 +4685,7 @@ public class DefaultCodegen implements CodegenConfig {
             for (Map.Entry<String, Header> headerEntry : response.getHeaders().entrySet()) {
                 String description = headerEntry.getValue().getDescription();
                 // follow the $ref
-                Header header = ModelUtils.getReferencedHeader(this.openAPI, headerEntry.getValue());
+                Header header = modelUtils.getReferencedHeader(headerEntry.getValue());
 
                 Schema schema;
                 if (header.getSchema() == null) {
@@ -4953,11 +4967,11 @@ public class DefaultCodegen implements CodegenConfig {
         return aliases;
     }
 
-    private static Boolean isAliasOfSimpleTypes(Schema schema) {
-        return (!ModelUtils.isObjectSchema(schema)
-                && !ModelUtils.isArraySchema(schema)
-                && !ModelUtils.isMapSchema(schema)
-                && !ModelUtils.isComposedSchema(schema)
+    private Boolean isAliasOfSimpleTypes(Schema schema) {
+        return (!modelUtils.isObjectSchema(schema)
+                && !modelUtils.isArraySchema(schema)
+                && !modelUtils.isMapSchema(schema)
+                && !modelUtils.isComposedSchema(schema)
                 && schema.getEnum() == null);
     }
 
@@ -5438,7 +5452,7 @@ public class DefaultCodegen implements CodegenConfig {
         }
 
         String varDataType = var.mostInnerItems != null ? var.mostInnerItems.dataType : var.dataType;
-        Optional<Schema> referencedSchema = ModelUtils.getSchemas(openAPI).entrySet().stream()
+        Optional<Schema> referencedSchema = modelUtils.getSchemas().entrySet().stream()
                 .filter(entry -> Objects.equals(varDataType, toModelName(entry.getKey())))
                 .map(Map.Entry::getValue)
                 .findFirst();
@@ -5616,7 +5630,7 @@ public class DefaultCodegen implements CodegenConfig {
     }
 
     private void addConsumesInfo(Operation operation, CodegenOperation codegenOperation) {
-        RequestBody requestBody = ModelUtils.getReferencedRequestBody(this.openAPI, operation.getRequestBody());
+        RequestBody requestBody = modelUtils.getReferencedRequestBody(operation.getRequestBody());
         if (requestBody == null || requestBody.getContent() == null || requestBody.getContent().isEmpty()) {
             return;
         }
@@ -5641,8 +5655,8 @@ public class DefaultCodegen implements CodegenConfig {
         }
     }
 
-    public static Set<String> getConsumesInfo(OpenAPI openAPI, Operation operation) {
-        RequestBody requestBody = ModelUtils.getReferencedRequestBody(openAPI, operation.getRequestBody());
+    public Set<String> getConsumesInfo(Operation operation) {
+        RequestBody requestBody = modelUtils.getReferencedRequestBody(operation.getRequestBody());
 
         if (requestBody == null || requestBody.getContent() == null || requestBody.getContent().isEmpty()) {
             return Collections.emptySet(); // return empty set
@@ -5650,8 +5664,8 @@ public class DefaultCodegen implements CodegenConfig {
         return requestBody.getContent().keySet();
     }
 
-    public boolean hasFormParameter(OpenAPI openAPI, Operation operation) {
-        Set<String> consumesInfo = getConsumesInfo(openAPI, operation);
+    public boolean hasFormParameter(Operation operation) {
+        Set<String> consumesInfo = getConsumesInfo(operation);
 
         if (consumesInfo == null || consumesInfo.isEmpty()) {
             return false;
@@ -5668,18 +5682,18 @@ public class DefaultCodegen implements CodegenConfig {
         return false;
     }
 
-    public boolean hasBodyParameter(OpenAPI openAPI, Operation operation) {
-        RequestBody requestBody = ModelUtils.getReferencedRequestBody(openAPI, operation.getRequestBody());
+    public boolean hasBodyParameter(Operation operation) {
+        RequestBody requestBody = modelUtils.getReferencedRequestBody(operation.getRequestBody());
         if (requestBody == null) {
             return false;
         }
 
-        Schema schema = ModelUtils.getSchemaFromRequestBody(requestBody);
-        return ModelUtils.getReferencedSchema(openAPI, schema) != null;
+        Schema schema = modelUtils.getSchemaFromRequestBody(requestBody);
+        return modelUtils.getReferencedSchema(schema) != null;
     }
 
     private void addProducesInfo(ApiResponse inputResponse, CodegenOperation codegenOperation) {
-        ApiResponse response = ModelUtils.getReferencedApiResponse(this.openAPI, inputResponse);
+        ApiResponse response = modelUtils.getReferencedApiResponse(inputResponse);
         if (response == null || response.getContent() == null || response.getContent().isEmpty()) {
             return;
         }
@@ -5711,11 +5725,10 @@ public class DefaultCodegen implements CodegenConfig {
     /**
      * returns the list of MIME types the APIs can produce
      *
-     * @param openAPI   current specification instance
      * @param operation Operation
      * @return a set of MIME types
      */
-    public static Set<String> getProducesInfo(final OpenAPI openAPI, final Operation operation) {
+    public Set<String> getProducesInfo(final Operation operation) {
         if (operation.getResponses() == null || operation.getResponses().isEmpty()) {
             return null;
         }
@@ -5723,7 +5736,7 @@ public class DefaultCodegen implements CodegenConfig {
         Set<String> produces = new TreeSet<String>();
 
         for (ApiResponse r : operation.getResponses().values()) {
-            ApiResponse response = ModelUtils.getReferencedApiResponse(openAPI, r);
+            ApiResponse response = modelUtils.getReferencedApiResponse(r);
             if (response.getContent() != null) {
                 produces.addAll(response.getContent().keySet());
             }
@@ -5766,8 +5779,8 @@ public class DefaultCodegen implements CodegenConfig {
     public List<CodegenParameter> fromRequestBodyToFormParameters(RequestBody body, Set<String> imports) {
         List<CodegenParameter> parameters = new ArrayList<CodegenParameter>();
         LOGGER.debug("debugging fromRequestBodyToFormParameters= " + body);
-        Schema schema = ModelUtils.getSchemaFromRequestBody(body);
-        schema = ModelUtils.getReferencedSchema(this.openAPI, schema);
+        Schema schema = modelUtils.getSchemaFromRequestBody(body);
+        schema = modelUtils.getReferencedSchema(schema);
         List<String> allRequired = new ArrayList<String>();
         Map<String, Schema> properties = new LinkedHashMap<>();
         addProperties(properties, allRequired, schema);
@@ -5779,7 +5792,7 @@ public class DefaultCodegen implements CodegenConfig {
                 // value => property schema
                 Schema s = entry.getValue();
                 // array of schema
-                if (ModelUtils.isArraySchema(s)) {
+                if (modelUtils.isArraySchema(s)) {
                     final ArraySchema arraySchema = (ArraySchema) s;
                     Schema inner = getSchemaItems(arraySchema);
 
@@ -5813,7 +5826,7 @@ public class DefaultCodegen implements CodegenConfig {
                         codegenProperty = codegenProperty.items;
                     }
 
-                } else if (ModelUtils.isMapSchema(s)) {
+                } else if (modelUtils.isMapSchema(s)) {
                     LOGGER.error("Map of form parameters not supported. Please report the issue to https://github.com/openapitools/openapi-generator if you need help.");
                     continue;
                 } else {
@@ -5838,7 +5851,7 @@ public class DefaultCodegen implements CodegenConfig {
         LOGGER.debug("Debugging fromFormProperty {}: {}", name, propertySchema);
         CodegenProperty codegenProperty = fromProperty(name, propertySchema);
 
-        ModelUtils.syncValidationProperties(propertySchema, codegenProperty);
+        modelUtils.syncValidationProperties(propertySchema, codegenProperty);
 
         codegenParameter.isFormParam = Boolean.TRUE;
         codegenParameter.baseName = codegenProperty.baseName;
@@ -5881,7 +5894,7 @@ public class DefaultCodegen implements CodegenConfig {
 
         // validation
         // handle maximum, minimum properly for int/long by removing the trailing ".0"
-        if (ModelUtils.isIntegerSchema(propertySchema)) {
+        if (modelUtils.isIntegerSchema(propertySchema)) {
             codegenParameter.maximum = propertySchema.getMaximum() == null ? null : String.valueOf(propertySchema.getMaximum().longValue());
             codegenParameter.minimum = propertySchema.getMinimum() == null ? null : String.valueOf(propertySchema.getMinimum().longValue());
         } else {
@@ -5953,7 +5966,7 @@ public class DefaultCodegen implements CodegenConfig {
                 codegenParameter.description = codegenProperty.getDescription();
                 codegenParameter.isNullable = codegenProperty.isNullable;
             } else {
-                if (ModelUtils.isMapSchema(schema)) {// http body is map
+                if (modelUtils.isMapSchema(schema)) {// http body is map
                     LOGGER.error("Map should be supported. Please report to openapi-generator github repo about the issue.");
                 } else if (codegenProperty != null) {
                     String codegenModelName, codegenModelDescription;
@@ -6013,21 +6026,21 @@ public class DefaultCodegen implements CodegenConfig {
 
         String name = null;
         LOGGER.debug("Request body = " + body);
-        Schema schema = ModelUtils.getSchemaFromRequestBody(body);
+        Schema schema = modelUtils.getSchemaFromRequestBody(body);
         if (schema == null) {
             throw new RuntimeException("Request body cannot be null. Possible cause: missing schema in body parameter (OAS v2): " + body);
         }
 
         if (StringUtils.isNotBlank(schema.get$ref())) {
-            name = ModelUtils.getSimpleRef(schema.get$ref());
+            name = modelUtils.getSimpleRef(schema.get$ref());
         }
-        schema = ModelUtils.getReferencedSchema(this.openAPI, schema);
+        schema = modelUtils.getReferencedSchema(schema);
 
-        ModelUtils.syncValidationProperties(schema, codegenParameter);
+        modelUtils.syncValidationProperties(schema, codegenParameter);
 
-        if (ModelUtils.isMapSchema(schema)) {
+        if (modelUtils.isMapSchema(schema)) {
             // Schema with additionalproperties: true (including composed schemas with additionalproperties: true)
-            if (ModelUtils.isGenerateAliasAsModel(schema) && StringUtils.isNotBlank(name)) {
+            if (modelUtils.isGenerateAliasAsModel(schema) && StringUtils.isNotBlank(name)) {
                 this.addBodyModelSchema(codegenParameter, name, schema, imports, bodyParameterName, true);
             } else {
                 Schema inner = getAdditionalProperties(schema);
@@ -6067,8 +6080,8 @@ public class DefaultCodegen implements CodegenConfig {
                 // set nullable
                 setParameterNullable(codegenParameter, codegenProperty);
             }
-        } else if (ModelUtils.isArraySchema(schema)) {
-            if (ModelUtils.isGenerateAliasAsModel(schema) && StringUtils.isNotBlank(name)) {
+        } else if (modelUtils.isArraySchema(schema)) {
+            if (modelUtils.isGenerateAliasAsModel(schema) && StringUtils.isNotBlank(name)) {
                 this.addBodyModelSchema(codegenParameter, name, schema, imports, bodyParameterName, true);
             } else {
                 final ArraySchema arraySchema = (ArraySchema) schema;
@@ -6114,7 +6127,7 @@ public class DefaultCodegen implements CodegenConfig {
                     codegenProperty = codegenProperty.items;
                 }
             }
-        } else if (ModelUtils.isFreeFormObject(openAPI, schema)) {
+        } else if (modelUtils.isFreeFormObject(schema)) {
             // HTTP request body is free form object
             CodegenProperty codegenProperty = fromProperty("FREE_FORM_REQUEST_BODY", schema);
             if (codegenProperty != null) {
@@ -6134,7 +6147,7 @@ public class DefaultCodegen implements CodegenConfig {
             // set nullable
             setParameterNullable(codegenParameter, codegenProperty);
 
-        } else if (ModelUtils.isObjectSchema(schema) || ModelUtils.isComposedSchema(schema)) {
+        } else if (modelUtils.isObjectSchema(schema) || modelUtils.isComposedSchema(schema)) {
             this.addBodyModelSchema(codegenParameter, name, schema, imports, bodyParameterName, false);
         } else {
             // HTTP request body is primitive type (e.g. integer, string, etc)
@@ -6484,7 +6497,7 @@ public class DefaultCodegen implements CodegenConfig {
                 }
                 continue;
             }
-            cm.oneOf.add(toModelName(ModelUtils.getSimpleRef(o.get$ref())));
+            cm.oneOf.add(toModelName(modelUtils.getSimpleRef(o.get$ref())));
         }
         cm.name = type;
         cm.classname = type;
@@ -6567,7 +6580,7 @@ public class DefaultCodegen implements CodegenConfig {
      *         properties are allowed.
      */
     protected Schema getAdditionalProperties(Schema schema) {
-        return ModelUtils.getAdditionalProperties(openAPI, schema);
+        return modelUtils.getAdditionalProperties(schema);
     }
 
     final protected static Pattern JSON_MIME_PATTERN = Pattern.compile("(?i)application\\/json(;.*)?");
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
index e63a9716bb9..26062026031 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultGenerator.java
@@ -18,6 +18,7 @@
 package org.openapitools.codegen;
 
 import com.google.common.collect.ImmutableList;
+import io.swagger.models.Model;
 import io.swagger.v3.core.util.Json;
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.Operation;
@@ -76,6 +77,7 @@ public class DefaultGenerator implements Generator {
     protected CodegenConfig config;
     protected ClientOptInput opts;
     protected OpenAPI openAPI;
+    protected ModelUtils modelUtils;
     protected CodegenIgnoreProcessor ignoreProcessor;
     private Boolean generateApis = null;
     private Boolean generateModels = null;
@@ -108,6 +110,7 @@ public class DefaultGenerator implements Generator {
     public Generator opts(ClientOptInput opts) {
         this.opts = opts;
         this.openAPI = opts.getOpenAPI();
+        this.modelUtils = new ModelUtils(openAPI);
         this.config = opts.getConfig();
         List<TemplateDefinition> userFiles = opts.getUserDefinedTemplates();
         if (userFiles != null) {
@@ -152,6 +155,10 @@ public class DefaultGenerator implements Generator {
         return this;
     }
 
+    public ModelUtils getModelUtils() {
+        return modelUtils;
+    }
+
     /**
      * Retrieves an instance to the configured template processor, available after user-defined options are
      * applied via {@link DefaultGenerator#opts(ClientOptInput)}.
@@ -397,7 +404,7 @@ public class DefaultGenerator implements Generator {
             return;
         }
 
-        final Map<String, Schema> schemas = ModelUtils.getSchemas(this.openAPI);
+        final Map<String, Schema> schemas = modelUtils.getSchemas();
         if (schemas == null) {
             LOGGER.warn("Skipping generation of models because specification document has no schemas.");
             return;
@@ -458,7 +465,7 @@ public class DefaultGenerator implements Generator {
 
                 Schema schema = schemas.get(name);
 
-                if (ModelUtils.isFreeFormObject(this.openAPI, schema)) { // check to see if it'a a free-form object
+                if (modelUtils.isFreeFormObject(schema)) { // check to see if it'a a free-form object
                     // there are 3 free form use cases
                     // 1. free form with no validation that is not allOf included in any composed schemas
                     // 2. free form with validation
@@ -472,17 +479,17 @@ public class DefaultGenerator implements Generator {
                         LOGGER.info("Model {} not generated since it's a free-form object", name);
                         continue;
                     }
-                } else if (ModelUtils.isMapSchema(schema)) { // check to see if it's a "map" model
+                } else if (modelUtils.isMapSchema(schema)) { // check to see if it's a "map" model
                     // A composed schema (allOf, oneOf, anyOf) is considered a Map schema if the additionalproperties attribute is set
                     // for that composed schema. However, in the case of a composed schema, the properties are defined or referenced
                     // in the inner schemas, and the outer schema does not have properties.
-                    if (!ModelUtils.isGenerateAliasAsModel(schema) && !ModelUtils.isComposedSchema(schema) && (schema.getProperties() == null || schema.getProperties().isEmpty())) {
+                    if (!modelUtils.isGenerateAliasAsModel(schema) && !modelUtils.isComposedSchema(schema) && (schema.getProperties() == null || schema.getProperties().isEmpty())) {
                         // schema without property, i.e. alias to map
                         LOGGER.info("Model {} not generated since it's an alias to map (without property) and `generateAliasAsModel` is set to false (default)", name);
                         continue;
                     }
-                } else if (ModelUtils.isArraySchema(schema)) { // check to see if it's an "array" model
-                    if (!ModelUtils.isGenerateAliasAsModel(schema) && (schema.getProperties() == null || schema.getProperties().isEmpty())) {
+                } else if (modelUtils.isArraySchema(schema)) { // check to see if it's an "array" model
+                    if (!modelUtils.isGenerateAliasAsModel(schema) && (schema.getProperties() == null || schema.getProperties().isEmpty())) {
                         // schema without property, i.e. alias to array
                         LOGGER.info("Model {} not generated since it's an alias to array (without property) and `generateAliasAsModel` is set to false (default)", name);
                         continue;
@@ -868,7 +875,7 @@ public class DefaultGenerator implements Generator {
 
         List<File> files = new ArrayList<>();
         // models
-        List<String> filteredSchemas = ModelUtils.getSchemasUsedOnlyInFormParam(openAPI);
+        List<String> filteredSchemas = modelUtils.getSchemasUsedOnlyInFormParam();
         List<Object> allModels = new ArrayList<>();
         generateModels(files, allModels, filteredSchemas);
         // apis
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/InlineModelResolver.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/InlineModelResolver.java
index 30ac18c43e3..f69502c9358 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/InlineModelResolver.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/InlineModelResolver.java
@@ -39,6 +39,7 @@ import java.util.stream.Collectors;
 
 public class InlineModelResolver {
     private OpenAPI openapi;
+    private ModelUtils modelUtils;
     private Map<String, Schema> addedModels = new HashMap<String, Schema>();
     private Map<String, String> generatedSignature = new HashMap<String, String>();
 
@@ -56,6 +57,7 @@ public class InlineModelResolver {
 
     void flatten(OpenAPI openapi) {
         this.openapi = openapi;
+        this.modelUtils = new ModelUtils(openapi);
 
         if (openapi.getComponents() == null) {
             openapi.setComponents(new Components());
@@ -116,7 +118,7 @@ public class InlineModelResolver {
             return;
         }
 
-        Schema model = ModelUtils.getSchemaFromRequestBody(requestBody);
+        Schema model = modelUtils.getSchemaFromRequestBody(requestBody);
         if (model instanceof ObjectSchema) {
             Schema obj = (Schema) model;
             if (obj.getType() == null || "object".equals(obj.getType())) {
@@ -266,11 +268,11 @@ public class InlineModelResolver {
 
         for (String key : responses.keySet()) {
             ApiResponse response = responses.get(key);
-            if (ModelUtils.getSchemaFromResponse(response) == null) {
+            if (modelUtils.getSchemaFromResponse(response) == null) {
                 continue;
             }
 
-            Schema property = ModelUtils.getSchemaFromResponse(response);
+            Schema property = modelUtils.getSchemaFromResponse(response);
             if (property instanceof ObjectSchema) {
                 ObjectSchema op = (ObjectSchema) property;
                 if (op.getProperties() != null && op.getProperties().size() > 0) {
@@ -318,7 +320,7 @@ public class InlineModelResolver {
                 }
             } else if (property instanceof MapSchema) {
                 MapSchema mp = (MapSchema) property;
-                Schema innerProperty = ModelUtils.getAdditionalProperties(openAPI, mp);
+                Schema innerProperty = modelUtils.getAdditionalProperties(mp);
                 if (innerProperty instanceof ObjectSchema) {
                     ObjectSchema op = (ObjectSchema) innerProperty;
                     if (op.getProperties() != null && op.getProperties().size() > 0) {
@@ -428,7 +430,7 @@ public class InlineModelResolver {
         List<String> modelNames = new ArrayList<String>(models.keySet());
         for (String modelName : modelNames) {
             Schema model = models.get(modelName);
-            if (ModelUtils.isComposedSchema(model)) {
+            if (modelUtils.isComposedSchema(model)) {
                 ComposedSchema m = (ComposedSchema) model;
                 // inline child schemas
                 flattenComposedChildren(openAPI, modelName + "_allOf", m.getAllOf());
@@ -439,7 +441,7 @@ public class InlineModelResolver {
                 Map<String, Schema> properties = m.getProperties();
                 flattenProperties(openAPI, properties, modelName);
                 fixStringModel(m);
-            } else if (ModelUtils.isArraySchema(model)) {
+            } else if (modelUtils.isArraySchema(model)) {
                 ArraySchema m = (ArraySchema) model;
                 Schema inner = m.getItems();
                 if (inner instanceof ObjectSchema) {
@@ -602,8 +604,8 @@ public class InlineModelResolver {
                     }
                 }
             }
-            if (ModelUtils.isMapSchema(property)) {
-                Schema inner = ModelUtils.getAdditionalProperties(openAPI, property);
+            if (modelUtils.isMapSchema(property)) {
+                Schema inner = modelUtils.getAdditionalProperties(property);
                 if (inner instanceof ObjectSchema) {
                     ObjectSchema op = (ObjectSchema) inner;
                     if (op.getProperties() != null && op.getProperties().size() > 0) {
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
index cf0de7a7388..0e18ff6509e 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/config/CodegenConfigurator.java
@@ -264,7 +264,7 @@ public class CodegenConfigurator {
 
     public CodegenConfigurator setGenerateAliasAsModel(boolean generateAliasAsModel) {
         workflowSettingsBuilder.withGenerateAliasAsModel(generateAliasAsModel);
-        ModelUtils.setGenerateAliasAsModel(generateAliasAsModel);
+        GlobalSettings.setProperty("generateAliasAsModelKey", String.valueOf(generateAliasAsModel));
         return this;
     }
 
@@ -508,9 +508,6 @@ public class CodegenConfigurator {
             GlobalSettings.setProperty(entry.getKey(), entry.getValue());
         }
 
-        // if caller resets GlobalSettings, we'll need to reset generateAliasAsModel. As noted in this method, this should be moved.
-        ModelUtils.setGenerateAliasAsModel(workflowSettings.isGenerateAliasAsModel());
-
         // TODO: Support custom spec loader implementations (https://github.com/OpenAPITools/openapi-generator/issues/844)
         final List<AuthorizationValue> authorizationValues = AuthParser.parse(this.auth);
         ParseOptions options = new ParseOptions();
@@ -523,13 +520,18 @@ public class CodegenConfigurator {
         // TODO: The line below could be removed when at least one of the issue below has been resolved.
         // https://github.com/swagger-api/swagger-parser/issues/1369
         // https://github.com/swagger-api/swagger-parser/pull/1374
-        //ModelUtils.getOpenApiVersion(specification, inputSpec, authorizationValues);
+        //modelUtils.getOpenApiVersion(specification, inputSpec, authorizationValues);
+
+        ModelUtils modelUtils = new ModelUtils(specification);
+
+        // if caller resets GlobalSettings, we'll need to reset generateAliasAsModel. As noted in this method, this should be moved.
+        modelUtils.setGenerateAliasAsModel(workflowSettings.isGenerateAliasAsModel());
 
         // NOTE: We will only expose errors+warnings if there are already errors in the spec.
         if (validationMessages.size() > 0) {
             Set<String> warnings = new HashSet<>();
             if (specification != null) {
-                List<String> unusedModels = ModelUtils.getUnusedSchemas(specification);
+                List<String> unusedModels = modelUtils.getUnusedSchemas();
                 if (unusedModels != null) {
                     unusedModels.forEach(name -> warnings.add("Unused model: " + name));
                 }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/ExampleGenerator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/ExampleGenerator.java
index 6a6a807c6f2..1740869b303 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/ExampleGenerator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/ExampleGenerator.java
@@ -17,6 +17,7 @@
 
 package org.openapitools.codegen.examples;
 
+import com.sun.org.apache.xpath.internal.operations.Mod;
 import io.swagger.v3.core.util.Json;
 import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.media.ArraySchema;
@@ -46,11 +47,13 @@ public class ExampleGenerator {
 
     protected Map<String, Schema> examples;
     private OpenAPI openAPI;
+    private ModelUtils modelUtils;
     private Random random;
 
     public ExampleGenerator(Map<String, Schema> examples, OpenAPI openAPI) {
         this.examples = examples;
         this.openAPI = openAPI;
+        this.modelUtils = new ModelUtils(openAPI);
         // use a fixed seed to make the "random" numbers reproducible.
         this.random = new Random("ExampleGenerator".hashCode());
     }
@@ -69,7 +72,7 @@ public class ExampleGenerator {
     }
 
     private List<Map<String, String>> generateFromResponseSchema(Schema responseSchema, Set<String> producesInfo) {
-        if (responseSchema.getExample() == null && StringUtils.isEmpty(responseSchema.get$ref()) && !ModelUtils.isArraySchema(responseSchema)) {
+        if (responseSchema.getExample() == null && StringUtils.isEmpty(responseSchema.get$ref()) && !modelUtils.isArraySchema(responseSchema)) {
             // no example provided
             return null;
         }
@@ -78,14 +81,14 @@ public class ExampleGenerator {
             return generate(responseSchema.getExample(), new ArrayList<>(producesInfo));
         }
 
-        if (ModelUtils.isArraySchema(responseSchema)) { // array of schema
+        if (modelUtils.isArraySchema(responseSchema)) { // array of schema
             ArraySchema as = (ArraySchema) responseSchema;
             if (as.getItems() != null && StringUtils.isEmpty(as.getItems().get$ref())) { // arary of primtive types
                 return generate((Map<String, Object>) responseSchema.getExample(),
                         new ArrayList<String>(producesInfo), as.getItems());
             } else if (as.getItems() != null && !StringUtils.isEmpty(as.getItems().get$ref())) { // array of model
                 return generate((Map<String, Object>) responseSchema.getExample(),
-                        new ArrayList<String>(producesInfo), ModelUtils.getSimpleRef(as.getItems().get$ref()));
+                        new ArrayList<String>(producesInfo), modelUtils.getSimpleRef(as.getItems().get$ref()));
             } else {
                 // TODO log warning message as such case is not handled at the moment
                 return null;
@@ -95,7 +98,7 @@ public class ExampleGenerator {
                     new ArrayList<String>(producesInfo), responseSchema);
         } else { // model
             return generate((Map<String, Object>) responseSchema.getExample(),
-                    new ArrayList<String>(producesInfo), ModelUtils.getSimpleRef(responseSchema.get$ref()));
+                    new ArrayList<String>(producesInfo), modelUtils.getSimpleRef(responseSchema.get$ref()));
         }
     }
 
@@ -118,7 +121,7 @@ public class ExampleGenerator {
                         output.add(kv);
                     }
                 } else if (property != null && mediaType.startsWith(MIME_TYPE_XML)) {
-                    String example = new XmlExampleGenerator(this.examples).toXml(property);
+                    String example = new XmlExampleGenerator(this.examples, openAPI).toXml(property);
                     if (example != null) {
                         kv.put(EXAMPLE, example);
                         output.add(kv);
@@ -165,7 +168,7 @@ public class ExampleGenerator {
                     }
                 } else if (modelName != null && mediaType.startsWith(MIME_TYPE_XML)) {
                     final Schema schema = this.examples.get(modelName);
-                    String example = new XmlExampleGenerator(this.examples).toXml(schema, 0, Collections.<String>emptySet());
+                    String example = new XmlExampleGenerator(this.examples, openAPI).toXml(schema, 0, Collections.<String>emptySet());
                     if (example != null) {
                         kv.put(EXAMPLE, example);
                         output.add(kv);
@@ -222,13 +225,13 @@ public class ExampleGenerator {
         if (property.getExample() != null) {
             LOGGER.debug("Example set in openapi spec, returning example: '{}'", property.getExample().toString());
             return property.getExample();
-        } else if (ModelUtils.isBooleanSchema(property)) {
+        } else if (modelUtils.isBooleanSchema(property)) {
             Object defaultValue = property.getDefault();
             if (defaultValue != null) {
                 return defaultValue;
             }
             return Boolean.TRUE;
-        } else if (ModelUtils.isArraySchema(property)) {
+        } else if (modelUtils.isArraySchema(property)) {
             Schema innerType = ((ArraySchema) property).getItems();
             if (innerType != null) {
                 int arrayLength = null == ((ArraySchema) property).getMaxItems() ? 2 : ((ArraySchema) property).getMaxItems();
@@ -241,45 +244,45 @@ public class ExampleGenerator {
                 }
                 return objectProperties;
             }
-        } else if (ModelUtils.isDateSchema(property)) {
+        } else if (modelUtils.isDateSchema(property)) {
             return "2000-01-23";
-        } else if (ModelUtils.isDateTimeSchema(property)) {
+        } else if (modelUtils.isDateTimeSchema(property)) {
             return "2000-01-23T04:56:07.000+00:00";
-        } else if (ModelUtils.isNumberSchema(property)) {
+        } else if (modelUtils.isNumberSchema(property)) {
             Double min = getPropertyValue(property.getMinimum());
             Double max = getPropertyValue(property.getMaximum());
-            if (ModelUtils.isFloatSchema(property)) { // float
+            if (modelUtils.isFloatSchema(property)) { // float
                 return (float) randomNumber(min, max);
-            } else if (ModelUtils.isDoubleSchema(property)) { // decimal/double
+            } else if (modelUtils.isDoubleSchema(property)) { // decimal/double
                 return BigDecimal.valueOf(randomNumber(min, max));
             } else { // no format defined
                 return randomNumber(min, max);
             }
-        } else if (ModelUtils.isFileSchema(property)) {
+        } else if (modelUtils.isFileSchema(property)) {
             return "";  // TODO
 
-        } else if (ModelUtils.isIntegerSchema(property)) {
+        } else if (modelUtils.isIntegerSchema(property)) {
             Double min = getPropertyValue(property.getMinimum());
             Double max = getPropertyValue(property.getMaximum());
-            if (ModelUtils.isLongSchema(property)) {
+            if (modelUtils.isLongSchema(property)) {
                 return (long) randomNumber(min, max);
             }
             return (int) randomNumber(min, max);
-        } else if (ModelUtils.isMapSchema(property)) {
+        } else if (modelUtils.isMapSchema(property)) {
             Map<String, Object> mp = new HashMap<String, Object>();
             if (property.getName() != null) {
                 mp.put(property.getName(),
-                        resolvePropertyToExample(propertyName, mediaType, ModelUtils.getAdditionalProperties(openAPI, property), processedModels));
+                        resolvePropertyToExample(propertyName, mediaType, modelUtils.getAdditionalProperties(property), processedModels));
             } else {
                 mp.put("key",
-                        resolvePropertyToExample(propertyName, mediaType, ModelUtils.getAdditionalProperties(openAPI, property), processedModels));
+                        resolvePropertyToExample(propertyName, mediaType, modelUtils.getAdditionalProperties(property), processedModels));
             }
             return mp;
-        } else if (ModelUtils.isUUIDSchema(property)) {
+        } else if (modelUtils.isUUIDSchema(property)) {
             return "046b6c7f-0b8a-43b9-b35d-6489e6daee91";
-        } else if (ModelUtils.isURISchema(property)) {
+        } else if (modelUtils.isURISchema(property)) {
             return "https://openapi-generator.tech";
-        } else if (ModelUtils.isStringSchema(property)) {
+        } else if (modelUtils.isStringSchema(property)) {
             LOGGER.debug("String property");
             String defaultValue = (String) property.getDefault();
             if (defaultValue != null && !defaultValue.isEmpty()) {
@@ -299,14 +302,14 @@ public class ExampleGenerator {
             LOGGER.debug("No values found, using property name " + propertyName + " as example");
             return propertyName;
         } else if (!StringUtils.isEmpty(property.get$ref())) { // model
-            String simpleName = ModelUtils.getSimpleRef(property.get$ref());
-            Schema schema = ModelUtils.getSchema(openAPI, simpleName);
+            String simpleName = modelUtils.getSimpleRef(property.get$ref());
+            Schema schema = modelUtils.getSchema(simpleName);
             if (schema == null) { // couldn't find the model/schema
                 return "{}";
             }
             return resolveModelToExample(simpleName, mediaType, schema, processedModels);
 
-        } else if (ModelUtils.isObjectSchema(property)) {
+        } else if (modelUtils.isObjectSchema(property)) {
             return "{}";
         }
 
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/XmlExampleGenerator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/XmlExampleGenerator.java
index 562fbe00469..e9e83c4e966 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/XmlExampleGenerator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/examples/XmlExampleGenerator.java
@@ -17,6 +17,7 @@
 
 package org.openapitools.codegen.examples;
 
+import io.swagger.v3.oas.models.OpenAPI;
 import io.swagger.v3.oas.models.media.ArraySchema;
 import io.swagger.v3.oas.models.media.Schema;
 import io.swagger.v3.oas.models.media.XML;
@@ -35,8 +36,12 @@ public class XmlExampleGenerator {
     public static String TAG_END = "</";
     private static String EMPTY = "";
     protected Map<String, Schema> examples;
+    protected OpenAPI openAPI;
+    protected ModelUtils modelUtils;
 
-    public XmlExampleGenerator(Map<String, Schema> examples) {
+    public XmlExampleGenerator(Map<String, Schema> examples, OpenAPI openAPI) {
+        this.openAPI = openAPI;
+        this.modelUtils = new ModelUtils(openAPI);
         this.examples = examples;
         if (examples == null) {
             this.examples = new HashMap<String, Schema>();
@@ -124,7 +129,7 @@ public class XmlExampleGenerator {
         }
         StringBuilder sb = new StringBuilder();
 
-        if (ModelUtils.isArraySchema(schema)) {
+        if (modelUtils.isArraySchema(schema)) {
             ArraySchema as = (ArraySchema) schema;
             Schema inner = as.getItems();
             boolean wrapped = false;
@@ -177,29 +182,29 @@ public class XmlExampleGenerator {
     protected String getExample(Schema schema) {
         if (schema.getExample() != null) {
             return schema.getExample().toString();
-        } else if (ModelUtils.isDateTimeSchema(schema)) {
+        } else if (modelUtils.isDateTimeSchema(schema)) {
             return "2000-01-23T04:56:07.000Z";
-        } else if (ModelUtils.isDateSchema(schema)) {
+        } else if (modelUtils.isDateSchema(schema)) {
             return "2000-01-23";
-        } else if (ModelUtils.isBooleanSchema(schema)) {
+        } else if (modelUtils.isBooleanSchema(schema)) {
             return "true";
-        } else if (ModelUtils.isNumberSchema(schema)) {
-            if (ModelUtils.isFloatSchema(schema)) { // float
+        } else if (modelUtils.isNumberSchema(schema)) {
+            if (modelUtils.isFloatSchema(schema)) { // float
                 return "1.3579";
             } else { // double
                 return "3.149";
             }
-        } else if (ModelUtils.isPasswordSchema(schema)) {
+        } else if (modelUtils.isPasswordSchema(schema)) {
             return "********";
-        } else if (ModelUtils.isUUIDSchema(schema)) {
+        } else if (modelUtils.isUUIDSchema(schema)) {
             return "046b6c7f-0b8a-43b9-b35d-6489e6daee91";
-        } else if (ModelUtils.isURISchema(schema)) {
+        } else if (modelUtils.isURISchema(schema)) {
             return "https://openapi-generator.tech";
             // do these last in case the specific types above are derived from these classes
-        } else if (ModelUtils.isStringSchema(schema)) {
+        } else if (modelUtils.isStringSchema(schema)) {
             return "aeiou";
-        } else if (ModelUtils.isIntegerSchema(schema)) {
-            if (ModelUtils.isLongSchema(schema)) { // long
+        } else if (modelUtils.isIntegerSchema(schema)) {
+            if (modelUtils.isLongSchema(schema)) { // long
                 return "123456789";
             } else { //integer
                 return "123";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractAdaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractAdaCodegen.java
index 0479852e2de..89c4970309d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractAdaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractAdaCodegen.java
@@ -410,12 +410,12 @@ abstract public class AbstractAdaCodegen extends DefaultCodegen implements Codeg
             schemaType = schemaType.replace("-", "_");
         }
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner) + "_Vectors.Vector";
         }
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             String name = getTypeDeclaration(inner) + "_Map";
             if (name.startsWith("Swagger.")) {
@@ -432,7 +432,7 @@ abstract public class AbstractAdaCodegen extends DefaultCodegen implements Codeg
             return schemaType;
         }
         String modelType = toModelName(schemaType).replace("-", "_");
-        if (ModelUtils.isStringSchema(p) || ModelUtils.isFileSchema(p)
+        if (modelUtils.isStringSchema(p) || modelUtils.isFileSchema(p)
                 || languageSpecificPrimitives.contains(modelType)) {
             return modelType;
         }
@@ -526,8 +526,8 @@ abstract public class AbstractAdaCodegen extends DefaultCodegen implements Codeg
 
         if (operation.getResponses() != null && !operation.getResponses().isEmpty()) {
             ApiResponse methodResponse = findMethodResponse(operation.getResponses());
-            if (methodResponse != null && ModelUtils.getSchemaFromResponse(methodResponse) != null) {
-                CodegenProperty cm = fromProperty("response", ModelUtils.getSchemaFromResponse(methodResponse));
+            if (methodResponse != null && modelUtils.getSchemaFromResponse(methodResponse) != null) {
+                CodegenProperty cm = fromProperty("response", modelUtils.getSchemaFromResponse(methodResponse));
                 op.vendorExtensions.put("x-codegen-response", cm);
                 op.vendorExtensions.put("x-is-model-type", isModelType(cm));
                 op.vendorExtensions.put("x-is-stream-type", isStreamType(cm));
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractApexCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractApexCodegen.java
index 6b0068ddb13..e6331ad6362 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractApexCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractApexCodegen.java
@@ -185,7 +185,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             if (inner == null) {
@@ -194,7 +194,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
                 return null;
             }
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
 
             if (inner == null) {
@@ -217,7 +217,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             final ArraySchema ap = (ArraySchema) p;
             final String pattern = "new ArrayList<%s>()";
             if (ap.getItems() == null) {
@@ -225,7 +225,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
             }
 
             return String.format(Locale.ROOT, pattern, getTypeDeclaration(ap.getItems()));
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             final MapSchema ap = (MapSchema) p;
             final String pattern = "new HashMap<%s>()";
             if (getAdditionalProperties(ap) == null) {
@@ -233,32 +233,32 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
             }
 
             return String.format(Locale.ROOT, pattern, String.format(Locale.ROOT, "String, %s", getTypeDeclaration(getAdditionalProperties(ap))));
-        } else if (ModelUtils.isLongSchema(p)) {
+        } else if (modelUtils.isLongSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString() + "l";
             }
             return "null";
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return "null";
-        } else if (ModelUtils.isFloatSchema(p)) {
+        } else if (modelUtils.isFloatSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString() + "f";
             }
             return "null";
-        } else if (ModelUtils.isDoubleSchema(p)) {
+        } else if (modelUtils.isDoubleSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString() + "d";
             }
             return "null";
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return "null";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 String _default = (String) p.getDefault();
                 if (p.getEnum() == null) {
@@ -314,18 +314,18 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
         Object obj = p.getExample();
         String example = obj == null ? "" : obj.toString();
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             example = "new " + getTypeDeclaration(p) + "{" + toExampleValue(
                     ((ArraySchema) p).getItems()) + "}";
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             example = String.valueOf(!"false".equals(example));
-        } else if (ModelUtils.isByteArraySchema(p)) {
+        } else if (modelUtils.isByteArraySchema(p)) {
             if (example.isEmpty()) {
                 example = "VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cu";
             }
             p.setExample(example);
             example = "EncodingUtil.base64Decode('" + example + "')";
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             if (example.matches("^\\d{4}(-\\d{2}){2}")) {
                 example = example.substring(0, 10).replaceAll("-0?", ", ");
             } else if (example.isEmpty()) {
@@ -336,7 +336,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
                 example = "2000, 1, 23";
             }
             example = "Date.newInstance(" + example + ")";
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             if (example.matches("^\\d{4}([-T:]\\d{2}){5}.+")) {
                 example = example.substring(0, 19).replaceAll("[-T:]0?", ", ");
             } else if (example.isEmpty()) {
@@ -347,31 +347,31 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
                 example = "2000, 1, 23, 4, 56, 7";
             }
             example = "Datetime.newInstanceGmt(" + example + ")";
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             example = example.replaceAll("[^-0-9.]", "");
             example = example.isEmpty() ? "1.3579" : example;
-        } else if (ModelUtils.isFileSchema(p)) {
+        } else if (modelUtils.isFileSchema(p)) {
             if (example.isEmpty()) {
                 example = "VGhlIHF1aWNrIGJyb3duIGZveCBqdW1wZWQgb3ZlciB0aGUgbGF6eSBkb2cu";
                 p.setExample(example);
             }
             example = "EncodingUtil.base64Decode(" + example + ")";
-        } else if (ModelUtils.isEmailSchema(p)) {
+        } else if (modelUtils.isEmailSchema(p)) {
             if (example.isEmpty()) {
                 example = "example@example.com";
                 p.setExample(example);
             }
             example = "'" + example + "'";
-        } else if (ModelUtils.isLongSchema(p)) {
+        } else if (modelUtils.isLongSchema(p)) {
             example = example.isEmpty() ? "123456789L" : example + "L";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             example = "new " + getTypeDeclaration(p) + "{'key'=>" + toExampleValue(getAdditionalProperties(p)) + "}";
 
-        } else if (ModelUtils.isPasswordSchema(p)) {
+        } else if (modelUtils.isPasswordSchema(p)) {
             example = example.isEmpty() ? "password123" : escapeText(example);
             p.setExample(example);
             example = "'" + example + "'";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             List<String> enums = p.getEnum();
             if (enums != null && example.isEmpty()) {
                 example = enums.get(0);
@@ -383,13 +383,13 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
                 p.setExample(example);
             }
             example = "'" + example + "'";
-        } else if (ModelUtils.isUUIDSchema(p)) {
+        } else if (modelUtils.isUUIDSchema(p)) {
             example = example.isEmpty()
                     ? "'046b6c7f-0b8a-43b9-b35d-6489e6daee91'"
                     : "'" + escapeText(example) + "'";
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             example = example.matches("^-?\\d+$") ? example : "0";
-        } else if (ModelUtils.isObjectSchema(p)) {
+        } else if (modelUtils.isObjectSchema(p)) {
             example = example.isEmpty() ? "null" : example;
         } else {
             example = getTypeDeclaration(p) + ".getExample()";
@@ -571,7 +571,7 @@ public abstract class AbstractApexCodegen extends DefaultCodegen implements Code
         if (op.getHasExamples()) {
             // prepare examples for Apex test classes
             ApiResponse apiResponse = findMethodResponse(operation.getResponses());
-            final Schema responseSchema = ModelUtils.getSchemaFromResponse(apiResponse);
+            final Schema responseSchema = modelUtils.getSchemaFromResponse(apiResponse);
             String deserializedExample = toExampleValue(responseSchema);
             for (Map<String, String> example : op.examples) {
                 example.put("example", escapeText(example.get("example")));
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
index 7f164bc961a..eb3b112ad75 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCSharpCodegen.java
@@ -437,7 +437,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
     private void postProcessEnumRefs(final Map<String, Object> models) {
         Map<String, CodegenModel> enumRefs = new HashMap<String, CodegenModel>();
         for (Map.Entry<String, Object> entry : models.entrySet()) {
-            CodegenModel model = ModelUtils.getModelByName(entry.getKey(), models);
+            CodegenModel model = modelUtils.getModelByName(entry.getKey(), models);
             if (model.isEnum) {
                 enumRefs.put(entry.getKey(), model);
             }
@@ -445,7 +445,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
 
         for (Map.Entry<String, Object> entry : models.entrySet()) {
             String openAPIName = entry.getKey();
-            CodegenModel model = ModelUtils.getModelByName(openAPIName, models);
+            CodegenModel model = modelUtils.getModelByName(openAPIName, models);
             if (model != null) {
                 for (CodegenProperty var : model.allVars) {
                     if (enumRefs.containsKey(var.dataType)) {
@@ -594,7 +594,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
     protected void updateValueTypeProperty(Map<String, Object> models) {
         for (Map.Entry<String, Object> entry : models.entrySet()) {
             String openAPIName = entry.getKey();
-            CodegenModel model = ModelUtils.getModelByName(openAPIName, models);
+            CodegenModel model = modelUtils.getModelByName(openAPIName, models);
             if (model != null) {
                 for (CodegenProperty var : model.vars) {
                     var.vendorExtensions.put("x-is-value-type", isValueType(var));
@@ -611,7 +611,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
     protected void updateNullableTypeProperty(Map<String, Object> models) {
         for (Map.Entry<String, Object> entry : models.entrySet()) {
             String openAPIName = entry.getKey();
-            CodegenModel model = ModelUtils.getModelByName(openAPIName, models);
+            CodegenModel model = modelUtils.getModelByName(openAPIName, models);
             if (model != null) {
                 for (CodegenProperty var : model.vars) {
                     if (!var.isContainer && (nullableType.contains(var.dataType) || var.isEnum)) {
@@ -859,23 +859,23 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
      */
     @Override
     public String toExampleValue(Schema p) {
-        if (ModelUtils.isStringSchema(p)) {
+        if (modelUtils.isStringSchema(p)) {
             if (p.getExample() != null) {
                 return "\"" + p.getExample().toString() + "\"";
             }
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (p.getExample() != null) {
                 return p.getExample().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getExample() != null) {
                 return p.getExample().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getExample() != null) {
                 return p.getExample().toString();
             }
@@ -891,33 +891,33 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
      */
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             }
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             }
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
-                if (ModelUtils.isFloatSchema(p)) { // float
+                if (modelUtils.isFloatSchema(p)) { // float
                     return p.getDefault().toString() + "F";
-                } else if (ModelUtils.isDoubleSchema(p)) { // double
+                } else if (modelUtils.isDoubleSchema(p)) { // double
                     return p.getDefault().toString() + "D";
                 } else {    // decimal
                     return p.getDefault().toString() + "M";
                 }
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 String _default = (String) p.getDefault();
                 if (p.getEnum() == null) {
@@ -989,7 +989,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             return getArrayTypeDeclaration((ArraySchema) p);
         }
         return super.toInstantiationType(p);
@@ -997,9 +997,9 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             return getArrayTypeDeclaration((ArraySchema) p);
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             // Should we also support maps of maps?
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "<string, " + getTypeDeclaration(inner) + ">";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCppCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCppCodegen.java
index f03ac52aece..82b52e72d64 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCppCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractCppCodegen.java
@@ -362,7 +362,7 @@ abstract public class AbstractCppCodegen extends DefaultCodegen implements Codeg
     public Map<String, Object> postProcessAllModels(Map<String, Object> objs){
         Map<String, Object> models = super.postProcessAllModels(objs);
         for (final Entry<String, Object> model : models.entrySet()) {
-            CodegenModel mo = ModelUtils.getModelByName(model.getKey(), models);
+            CodegenModel mo = modelUtils.getModelByName(model.getKey(), models);
             addForwardDeclarations(mo, models);
         }
         return models;
@@ -379,7 +379,7 @@ abstract public class AbstractCppCodegen extends DefaultCodegen implements Codeg
             }
             String childPropertyType = property.isContainer? property.mostInnerItems.baseType : property.baseType;
             for(final Entry<String, Object> mo : objs.entrySet()) {
-                CodegenModel childModel = ModelUtils.getModelByName(mo.getKey(), objs);
+                CodegenModel childModel = modelUtils.getModelByName(mo.getKey(), objs);
                 if( !childPropertyType.equals(childModel.classname) || childPropertyType.equals(parentModel.classname) || !childModel.hasVars ){
                     continue;
                 }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractEiffelCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractEiffelCodegen.java
index f80183a7efb..ca1275a8dab 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractEiffelCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractEiffelCodegen.java
@@ -292,11 +292,11 @@ public abstract class AbstractEiffelCodegen extends DefaultCodegen implements Co
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "LIST [" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
 
             return getSchemaType(p) + " [" + getTypeDeclaration(inner) + "]";
@@ -463,7 +463,7 @@ public abstract class AbstractEiffelCodegen extends DefaultCodegen implements Co
 
     private void postProcessParentModels(final Map<String, Object> models) {
         for (final String parent : parentModels) {
-            final CodegenModel parentModel = ModelUtils.getModelByName(parent, models);
+            final CodegenModel parentModel = modelUtils.getModelByName(parent, models);
             final Collection<CodegenModel> childrenModels = childrenByParent.get(parent);
             for (final CodegenModel child : childrenModels) {
                 processParentPropertiesInChildModel(parentModel, child);
@@ -492,7 +492,7 @@ public abstract class AbstractEiffelCodegen extends DefaultCodegen implements Co
 
     @Override
     public CodegenModel fromModel(String name, Schema model) {
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel codegenModel = super.fromModel(name, model);
         if (allDefinitions != null && codegenModel.parentSchema != null && codegenModel.hasEnums) {
             final Schema parentModel = allDefinitions.get(codegenModel.parentSchema);
@@ -571,7 +571,7 @@ public abstract class AbstractEiffelCodegen extends DefaultCodegen implements Co
     @Override
     public String toInstantiationType(Schema p) {
         return getTypeDeclaration(p);
-//        if (ModelUtils.isMapSchema(p)) {
+//        if (modelUtils.isMapSchema(p)) {
 //            Schema additionalProperties2 = getAdditionalProperties(p);
 //            String type = additionalProperties2.getType();
 //            if (null == type) {
@@ -580,7 +580,7 @@ public abstract class AbstractEiffelCodegen extends DefaultCodegen implements Co
 //            }
 //            String inner = toModelName(getSchemaType(additionalProperties2));
 //            return instantiationTypes.get("map") + " [" + inner + "]";
-//        } else if (ModelUtils.isArraySchema(p)) {
+//        } else if (modelUtils.isArraySchema(p)) {
 //            ArraySchema ap = (ArraySchema) p;
 //            String inner = toModelName(getSchemaType(ap.getItems()));
 //            return instantiationTypes.get("array") + " [" + inner + "]";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractFSharpCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractFSharpCodegen.java
index c2e3fee78da..0732ad5fc81 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractFSharpCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractFSharpCodegen.java
@@ -358,7 +358,7 @@ public abstract class AbstractFSharpCodegen extends DefaultCodegen implements Co
         List<String> classNames = new ArrayList<String>();
 
         for (String k : objs.keySet()) {
-            CodegenModel model = ModelUtils.getModelByName(k, objs);
+            CodegenModel model = modelUtils.getModelByName(k, objs);
             if (model == null || model.classname == null) {
                 throw new RuntimeException("Null model encountered");
             }
@@ -405,7 +405,7 @@ public abstract class AbstractFSharpCodegen extends DefaultCodegen implements Co
     private void postProcessEnumRefs(final Map<String, Object> models) {
         Map<String, CodegenModel> enumRefs = new HashMap<String, CodegenModel>();
         for (Map.Entry<String, Object> entry : models.entrySet()) {
-            CodegenModel model = ModelUtils.getModelByName(entry.getKey(), models);
+            CodegenModel model = modelUtils.getModelByName(entry.getKey(), models);
             if (model.isEnum) {
                 enumRefs.put(entry.getKey(), model);
             }
@@ -413,7 +413,7 @@ public abstract class AbstractFSharpCodegen extends DefaultCodegen implements Co
 
         for (Map.Entry<String, Object> entry : models.entrySet()) {
             String openAPIName = entry.getKey();
-            CodegenModel model = ModelUtils.getModelByName(openAPIName, models);
+            CodegenModel model = modelUtils.getModelByName(openAPIName, models);
             if (model != null) {
                 for (CodegenProperty var : model.allVars) {
                     if (enumRefs.containsKey(var.dataType)) {
@@ -735,23 +735,23 @@ public abstract class AbstractFSharpCodegen extends DefaultCodegen implements Co
      */
     @Override
     public String toExampleValue(Schema p) {
-        if (ModelUtils.isStringSchema(p)) {
+        if (modelUtils.isStringSchema(p)) {
             if (p.getExample() != null) {
                 return "\"" + p.getExample().toString() + "\"";
             }
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (p.getExample() != null) {
                 return p.getExample().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getExample() != null) {
                 return p.getExample().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getExample() != null) {
                 return p.getExample().toString();
             }
@@ -768,33 +768,33 @@ public abstract class AbstractFSharpCodegen extends DefaultCodegen implements Co
      */
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             }
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             }
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
-                if (ModelUtils.isFloatSchema(p)) { // float
+                if (modelUtils.isFloatSchema(p)) { // float
                     return p.getDefault().toString() + "F";
-                } else if (ModelUtils.isDoubleSchema(p)) { // double
+                } else if (modelUtils.isDoubleSchema(p)) { // double
                     return p.getDefault().toString() + "D";
                 } else {    // decimal
                     return p.getDefault().toString() + "M";
                 }
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 String _default = (String) p.getDefault();
                 if (p.getEnum() == null) {
@@ -817,7 +817,7 @@ public abstract class AbstractFSharpCodegen extends DefaultCodegen implements Co
 
     public String getNullableType(Schema p, String type) {
         if (languageSpecificPrimitives.contains(type)) {
-            if (isSupportNullable() && ModelUtils.isNullable(p) && nullableType.contains(type)) {
+            if (isSupportNullable() && modelUtils.isNullable(p) && nullableType.contains(type)) {
                 return type + " option";
             } else {
                 return type;
@@ -869,7 +869,7 @@ public abstract class AbstractFSharpCodegen extends DefaultCodegen implements Co
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             return getArrayTypeDeclaration((ArraySchema) p);
         }
         return super.toInstantiationType(p);
@@ -877,9 +877,9 @@ public abstract class AbstractFSharpCodegen extends DefaultCodegen implements Co
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             return getArrayTypeDeclaration((ArraySchema) p);
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             // Should we also support maps of maps?
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "<string, " + getTypeDeclaration(inner) + ">";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGoCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGoCodegen.java
index d9eff4ad3be..665a119d931 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGoCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGoCodegen.java
@@ -331,7 +331,7 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             // In OAS 3.0.x, the array "items" attribute is required.
@@ -339,7 +339,7 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
             // specification is aligned with the JSON schema specification.
             // When "items" is not specified, the elements of the array may be anything at all.
             if (inner != null) {
-                inner = ModelUtils.unaliasSchema(this.openAPI, inner);
+                inner = modelUtils.unaliasSchema(inner);
             }
             String typDecl;
             if (inner != null) {
@@ -348,9 +348,9 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
                 typDecl = "interface{}";
             }
             return "[]" + typDecl;
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
-            return getSchemaType(p) + "[string]" + getTypeDeclaration(ModelUtils.unaliasSchema(this.openAPI, inner));
+            return getSchemaType(p) + "[string]" + getTypeDeclaration(modelUtils.unaliasSchema(inner));
         }
         //return super.getTypeDeclaration(p);
 
@@ -395,7 +395,7 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
 
         if (ref != null && !ref.isEmpty()) {
             type = openAPIType;
-        } else if ("object".equals(openAPIType) && ModelUtils.isAnyTypeSchema(openAPI, p)) {
+        } else if ("object".equals(openAPIType) && modelUtils.isAnyTypeSchema(p)) {
             // Arbitrary type. Note this is not the same thing as free-form object.
             type = "interface{}";
         } else if (typeMapping.containsKey(openAPIType)) {
@@ -426,9 +426,9 @@ public abstract class AbstractGoCodegen extends DefaultCodegen implements Codege
      */
     @Override
     public String toInstantiationType(Schema property) {
-        if (ModelUtils.isMapSchema(property)) {
+        if (modelUtils.isMapSchema(property)) {
             return getTypeDeclaration(property);
-        } else if (ModelUtils.isArraySchema(property)) {
+        } else if (modelUtils.isArraySchema(property)) {
             return getTypeDeclaration(property);
         }
         return super.toInstantiationType(property);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGraphQLCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGraphQLCodegen.java
index ddfaa16c86a..664b53351ed 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGraphQLCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractGraphQLCodegen.java
@@ -266,11 +266,11 @@ public abstract class AbstractGraphQLCodegen extends DefaultCodegen implements C
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = (Schema) p.getAdditionalProperties();
             return getTypeDeclaration(inner);
         }
@@ -278,7 +278,7 @@ public abstract class AbstractGraphQLCodegen extends DefaultCodegen implements C
         // Not using the supertype invocation, because we want to UpperCamelize
         // the type.
         String schemaType = getSchemaType(p);
-        String nullable = ModelUtils.isNullable(p) ? "" : "!";
+        String nullable = modelUtils.isNullable(p) ? "" : "!";
         /*
         if (p != null && Boolean.TRUE.equals(p.getNullable())) {
             nullable = "";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
index 8bddc1feaf5..1b989264a6f 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractJavaCodegen.java
@@ -794,13 +794,13 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        Schema<?> schema = ModelUtils.unaliasSchema(this.openAPI, p, importMapping);
-        Schema<?> target = ModelUtils.isGenerateAliasAsModel() ? p : schema;
-        if (ModelUtils.isArraySchema(target)) {
+        Schema<?> schema = modelUtils.unaliasSchema(p, importMapping);
+        Schema<?> target = modelUtils.isGenerateAliasAsModel() ? p : schema;
+        if (modelUtils.isArraySchema(target)) {
             Schema<?> items = getSchemaItems((ArraySchema) schema);
             return getSchemaType(target) + "<" + getTypeDeclaration(items) + ">";
-        } else if (ModelUtils.isMapSchema(target)) {
-            // Note: ModelUtils.isMapSchema(p) returns true when p is a composed schema that also defines
+        } else if (modelUtils.isMapSchema(target)) {
+            // Note: modelUtils.isMapSchema(p) returns true when p is a composed schema that also defines
             // additionalproperties: true
             Schema<?> inner = getAdditionalProperties(target);
             if (inner == null) {
@@ -823,10 +823,10 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
 
     @Override
     public String toDefaultValue(Schema schema) {
-        schema = ModelUtils.getReferencedSchema(this.openAPI, schema);
-        if (ModelUtils.isArraySchema(schema)) {
+        schema = modelUtils.getReferencedSchema(schema);
+        if (modelUtils.isArraySchema(schema)) {
             final String pattern;
-            if (ModelUtils.isSet(schema)) {
+            if (modelUtils.isSet(schema)) {
                 String mapInstantiationType = instantiationTypes().getOrDefault("set", "LinkedHashSet");
                 pattern = "new " + mapInstantiationType + "<%s>()";
             } else {
@@ -836,7 +836,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
 
             Schema<?> items = getSchemaItems((ArraySchema) schema);
 
-            String typeDeclaration = getTypeDeclaration(ModelUtils.unaliasSchema(this.openAPI, items));
+            String typeDeclaration = getTypeDeclaration(modelUtils.unaliasSchema(items));
             Object java8obj = additionalProperties.get("java8");
             if (java8obj != null) {
                 Boolean java8 = Boolean.valueOf(java8obj.toString());
@@ -846,7 +846,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             }
 
             return String.format(Locale.ROOT, pattern, typeDeclaration);
-        } else if (ModelUtils.isMapSchema(schema) && !(schema instanceof ComposedSchema)) {
+        } else if (modelUtils.isMapSchema(schema) && !(schema instanceof ComposedSchema)) {
             if (schema.getProperties() != null && schema.getProperties().size() > 0) {
                 // object is complex object with free-form additional properties
                 if (schema.getDefault() != null) {
@@ -872,7 +872,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             }
 
             return String.format(Locale.ROOT, pattern, typeDeclaration);
-        } else if (ModelUtils.isIntegerSchema(schema)) {
+        } else if (modelUtils.isIntegerSchema(schema)) {
             if (schema.getDefault() != null) {
                 if (SchemaTypeUtil.INTEGER64_FORMAT.equals(schema.getFormat())) {
                     return schema.getDefault().toString() + "l";
@@ -881,7 +881,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                 }
             }
             return null;
-        } else if (ModelUtils.isNumberSchema(schema)) {
+        } else if (modelUtils.isNumberSchema(schema)) {
             if (schema.getDefault() != null) {
                 if (SchemaTypeUtil.FLOAT_FORMAT.equals(schema.getFormat())) {
                     return schema.getDefault().toString() + "f";
@@ -892,17 +892,17 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                 }
             }
             return null;
-        } else if (ModelUtils.isBooleanSchema(schema)) {
+        } else if (modelUtils.isBooleanSchema(schema)) {
             if (schema.getDefault() != null) {
                 return schema.getDefault().toString();
             }
             return null;
-        } else if (ModelUtils.isURISchema(schema)) {
+        } else if (modelUtils.isURISchema(schema)) {
             if (schema.getDefault() != null) {
                 return "URI.create(\"" + escapeText((String) schema.getDefault()) + "\")";
             }
             return null;
-        } else if (ModelUtils.isStringSchema(schema)) {
+        } else if (modelUtils.isStringSchema(schema)) {
             if (schema.getDefault() != null) {
                 String _default;
                 if (schema.getDefault() instanceof Date) {
@@ -923,7 +923,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                 }
             }
             return null;
-        } else if (ModelUtils.isObjectSchema(schema)) {
+        } else if (modelUtils.isObjectSchema(schema)) {
             if (schema.getDefault() != null) {
                 return super.toDefaultValue(schema);
             }
@@ -1100,7 +1100,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
 
     @Override
     public CodegenModel fromModel(String name, Schema model) {
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel codegenModel = super.fromModel(name, model);
         if (codegenModel.description != null) {
             codegenModel.imports.add("ApiModel");
@@ -1213,13 +1213,13 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                 }
                 for (Operation operation : path.readOperations()) {
                     LOGGER.info("Processing operation " + operation.getOperationId());
-                    if (hasBodyParameter(openAPI, operation) || hasFormParameter(openAPI, operation)) {
-                        String defaultContentType = hasFormParameter(openAPI, operation) ? "application/x-www-form-urlencoded" : "application/json";
-                        List<String> consumes = new ArrayList<>(getConsumesInfo(openAPI, operation));
+                    if (hasBodyParameter(operation) || hasFormParameter(operation)) {
+                        String defaultContentType = hasFormParameter(operation) ? "application/x-www-form-urlencoded" : "application/json";
+                        List<String> consumes = new ArrayList<>(getConsumesInfo(operation));
                         String contentType = consumes == null || consumes.isEmpty() ? defaultContentType : consumes.get(0);
                         operation.addExtension("x-contentType", contentType);
                     }
-                    String accepts = getAccept(openAPI, operation);
+                    String accepts = getAccept(operation);
                     operation.addExtension("x-accepts", accepts);
 
                 }
@@ -1271,10 +1271,10 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         }
     }
 
-    private static String getAccept(OpenAPI openAPI, Operation operation) {
+    private String getAccept(Operation operation) {
         String accepts = null;
         String defaultContentType = "application/json";
-        Set<String> producesInfo = getProducesInfo(openAPI, operation);
+        Set<String> producesInfo = getProducesInfo(operation);
         if (producesInfo != null && !producesInfo.isEmpty()) {
             ArrayList<String> produces = new ArrayList<>(producesInfo);
             StringBuilder sb = new StringBuilder();
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java
index 33ac8a95bb1..a9bf1278ebe 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractKotlinCodegen.java
@@ -310,13 +310,13 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        Schema<?> schema = ModelUtils.unaliasSchema(this.openAPI, p, importMapping);
-        Schema<?> target = ModelUtils.isGenerateAliasAsModel() ? p : schema;
-        if (ModelUtils.isArraySchema(target)) {
+        Schema<?> schema = modelUtils.unaliasSchema(p, importMapping);
+        Schema<?> target = modelUtils.isGenerateAliasAsModel() ? p : schema;
+        if (modelUtils.isArraySchema(target)) {
             Schema<?> items = getSchemaItems((ArraySchema) schema);
             return getSchemaType(target) + "<" + getTypeDeclaration(items) + ">";
-        } else if (ModelUtils.isMapSchema(target)) {
-            // Note: ModelUtils.isMapSchema(p) returns true when p is a composed schema that also defines
+        } else if (modelUtils.isMapSchema(target)) {
+            // Note: modelUtils.isMapSchema(p) returns true when p is a composed schema that also defines
             // additionalproperties: true
             Schema<?> inner = getAdditionalProperties(target);
             if (inner == null) {
@@ -899,27 +899,27 @@ public abstract class AbstractKotlinCodegen extends DefaultCodegen implements Co
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isURISchema(p)) {
+        } else if (modelUtils.isURISchema(p)) {
             if (p.getDefault() != null) {
                 return "URI.create('" + p.getDefault() + "')";
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault() + "\"";
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java
index 3b0efcaa380..d928227c7e3 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPhpCodegen.java
@@ -293,7 +293,7 @@ public abstract class AbstractPhpCodegen extends DefaultCodegen implements Codeg
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             if (inner == null) {
@@ -301,7 +301,7 @@ public abstract class AbstractPhpCodegen extends DefaultCodegen implements Codeg
                 inner = new StringSchema().description("TODO default missing array inner type to string");
             }
             return getTypeDeclaration(inner) + "[]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             if (inner == null) {
                 LOGGER.warn(p.getName() + "(map property) does not have a proper inner type defined. Default to string");
@@ -514,23 +514,23 @@ public abstract class AbstractPhpCodegen extends DefaultCodegen implements Codeg
      */
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "'" + p.getDefault() + "'";
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonConnexionServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonConnexionServerCodegen.java
index e1acbc1e166..baa8d935478 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonConnexionServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractPythonConnexionServerCodegen.java
@@ -345,11 +345,11 @@ public abstract class AbstractPythonConnexionServerCodegen extends DefaultCodege
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[str, " + getTypeDeclaration(inner) + "]";
         }
@@ -704,26 +704,26 @@ public abstract class AbstractPythonConnexionServerCodegen extends DefaultCodege
      */
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 if (p.getDefault().toString().equalsIgnoreCase("false"))
                     return "False";
                 else
                     return "True";
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "'" + (String) p.getDefault() + "'";
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java
index 5143cc5e943..0a7e99c30a0 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractRubyCodegen.java
@@ -114,10 +114,10 @@ abstract public class AbstractRubyCodegen extends DefaultCodegen implements Code
 
     @Override
     public String getTypeDeclaration(Schema schema) {
-        if (ModelUtils.isArraySchema(schema)) {
+        if (modelUtils.isArraySchema(schema)) {
             Schema inner = ((ArraySchema) schema).getItems();
             return getSchemaType(schema) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(schema)) {
+        } else if (modelUtils.isMapSchema(schema)) {
             Schema inner = getAdditionalProperties(schema);
             return getSchemaType(schema) + "<String, " + getTypeDeclaration(inner) + ">";
         }
@@ -127,11 +127,11 @@ abstract public class AbstractRubyCodegen extends DefaultCodegen implements Code
 
     @Override
     public String toInstantiationType(Schema schema) {
-        if (ModelUtils.isMapSchema(schema)) {
+        if (modelUtils.isMapSchema(schema)) {
             return instantiationTypes.get("map");
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             String parentType;
-            if (ModelUtils.isSet(schema)) {
+            if (modelUtils.isSet(schema)) {
                 parentType = "set";
             } else {
                 parentType = "array";
@@ -143,12 +143,12 @@ abstract public class AbstractRubyCodegen extends DefaultCodegen implements Code
 
     @Override
     public String toDefaultValue(Schema p) {
-        p = ModelUtils.getReferencedSchema(this.openAPI, p);
-        if (ModelUtils.isIntegerSchema(p) || ModelUtils.isNumberSchema(p) || ModelUtils.isBooleanSchema(p)) {
+        p = modelUtils.getReferencedSchema(p);
+        if (modelUtils.isIntegerSchema(p) || modelUtils.isNumberSchema(p) || modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 if (p.getDefault() instanceof Date) {
                     Date date = (Date) p.getDefault();
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java
index 6f87d96f13e..4cca652ffde 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractScalaCodegen.java
@@ -320,11 +320,11 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
 
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
@@ -335,7 +335,7 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
     @Override
     public String getSchemaType(Schema p) {
         String openAPIType = super.getSchemaType(p);
-        if (ModelUtils.isSet(p)) {
+        if (modelUtils.isSet(p)) {
             openAPIType = "set";
         }
 
@@ -353,13 +353,13 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
             return instantiationTypes.get("map") + "[String, " + inner + "]";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
-            return ( ModelUtils.isSet(ap) ? instantiationTypes.get("set") : instantiationTypes.get("array") ) + "[" + inner + "]";
+            return ( modelUtils.isSet(ap) ? instantiationTypes.get("set") : instantiationTypes.get("array") ) + "[" + inner + "]";
         } else {
             return null;
         }
@@ -372,24 +372,24 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
         }
 
         // comment out the following as the default value is no handled differently
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return null;
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return null;
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return null;
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             return null;
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             return null;
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
             return "new HashMap[String, " + inner + "]() ";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
             String genericType;
-            if (ModelUtils.isSet(ap)) {
+            if (modelUtils.isSet(ap)) {
                 genericType = instantiationTypes.get("set");
             } else {
                 genericType = instantiationTypes.get("array");
@@ -410,7 +410,7 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
 
             // Assume that any other generic types can be new'd up.
             return "new " + genericType + "[" + inner + "]() ";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             return null;
         } else {
             return null;
@@ -427,9 +427,9 @@ public abstract class AbstractScalaCodegen extends DefaultCodegen {
     @Override
     public CodegenProperty fromProperty(String name, Schema p) {
         CodegenProperty prop = super.fromProperty(name, p);
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema as = (ArraySchema) p;
-            if (ModelUtils.isSet(as)) {
+            if (modelUtils.isSet(as)) {
                 prop.containerType = "set";
             }
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
index a74b43a2575..0f50c948358 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AbstractTypeScriptClientCodegen.java
@@ -413,16 +413,16 @@ public abstract class AbstractTypeScriptClientCodegen extends DefaultCodegen imp
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             Schema<?> items = getSchemaItems((ArraySchema) p);
-            return getSchemaType(p) + "<" + getTypeDeclaration(ModelUtils.unaliasSchema(this.openAPI, items)) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+            return getSchemaType(p) + "<" + getTypeDeclaration(modelUtils.unaliasSchema(items)) + ">";
+        } else if (modelUtils.isMapSchema(p)) {
             Schema<?> inner = getSchemaAdditionalProperties(p);
             String nullSafeSuffix = getNullSafeAdditionalProps() ? " | undefined" : "";
-            return "{ [key: string]: " + getTypeDeclaration(ModelUtils.unaliasSchema(this.openAPI, inner)) + nullSafeSuffix  + "; }";
-        } else if (ModelUtils.isFileSchema(p)) {
+            return "{ [key: string]: " + getTypeDeclaration(modelUtils.unaliasSchema(inner)) + nullSafeSuffix  + "; }";
+        } else if (modelUtils.isFileSchema(p)) {
             return "any";
-        } else if (ModelUtils.isBinarySchema(p)) {
+        } else if (modelUtils.isBinarySchema(p)) {
             return "any";
         }
         return super.getTypeDeclaration(p);
@@ -432,37 +432,37 @@ public abstract class AbstractTypeScriptClientCodegen extends DefaultCodegen imp
     protected String getParameterDataType(Parameter parameter, Schema p) {
         // handle enums of various data types
         Schema inner;
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema mp1 = (ArraySchema) p;
             inner = mp1.getItems();
             return this.getSchemaType(p) + "<" + this.getParameterDataType(parameter, inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             inner = getAdditionalProperties(p);
             return "{ [key: string]: " + this.getParameterDataType(parameter, inner) + "; }";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             // Handle string enums
             if (p.getEnum() != null) {
                 return enumValuesToEnumTypeUnion(p.getEnum(), "string");
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             // Handle integer enums
             if (p.getEnum() != null) {
                 return numericEnumValuesToEnumTypeUnion(new ArrayList<Number>(p.getEnum()));
             }
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             // Handle double enums
             if (p.getEnum() != null) {
                 return numericEnumValuesToEnumTypeUnion(new ArrayList<Number>(p.getEnum()));
             }
         }
         /* TODO revise the logic below
-        else if (ModelUtils.isDateSchema(p)) {
+        else if (modelUtils.isDateSchema(p)) {
             // Handle date enums
             DateSchema sp = (DateSchema) p;
             if (sp.getEnum() != null) {
                 return enumValuesToEnumTypeUnion(sp.getEnum(), "string");
             }
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // Handle datetime enums
             DateTimeSchema sp = (DateTimeSchema) p;
             if (sp.getEnum() != null) {
@@ -510,27 +510,27 @@ public abstract class AbstractTypeScriptClientCodegen extends DefaultCodegen imp
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return UNDEFINED_VALUE;
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return UNDEFINED_VALUE;
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return UNDEFINED_VALUE;
-        } else if (ModelUtils.isNumberSchema(p) || ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p) || modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return UNDEFINED_VALUE;
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "'" + (String) p.getDefault() + "'";
             }
@@ -551,7 +551,7 @@ public abstract class AbstractTypeScriptClientCodegen extends DefaultCodegen imp
     public String getSchemaType(Schema p) {
         String openAPIType = super.getSchemaType(p);
         String type = null;
-        if (ModelUtils.isComposedSchema(p)) {
+        if (modelUtils.isComposedSchema(p)) {
             return openAPIType;
         } else if (typeMapping.containsKey(openAPIType)) {
             type = typeMapping.get(openAPIType);
@@ -898,7 +898,7 @@ public abstract class AbstractTypeScriptClientCodegen extends DefaultCodegen imp
 
         return filteredSchemas.stream().map(schema -> {
             String schemaType = getSchemaType(schema);
-            if (ModelUtils.isArraySchema(schema)) {
+            if (modelUtils.isArraySchema(schema)) {
                 ArraySchema ap = (ArraySchema) schema;
                 Schema inner = ap.getItems();
                 schemaType = schemaType + "<" + getSchemaType(inner) + ">";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AndroidClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AndroidClientCodegen.java
index 3f87fcc77c3..3a3d0dbfbd8 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AndroidClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AndroidClientCodegen.java
@@ -223,11 +223,11 @@ public class AndroidClientCodegen extends DefaultCodegen implements CodegenConfi
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
 
             return getSchemaType(p) + "<String, " + getTypeDeclaration(inner) + ">";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ApexClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ApexClientCodegen.java
index fe7cdcfb59d..88b244f6f95 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ApexClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ApexClientCodegen.java
@@ -221,24 +221,24 @@ public class ApexClientCodegen extends AbstractApexCodegen {
     @Override
     public String toDefaultValue(Schema p) {
         String out = null;
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             Schema inner = ((ArraySchema) p).getItems();
             out = String.format(
                     Locale.ROOT,
                     "new List<%s>()",
                     inner == null ? "Object" : getTypeDeclaration(inner)
             );
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             // true => "true", false => "false", null => "null"
             out = String.valueOf(p.getDefault());
-        } else if (ModelUtils.isLongSchema(p)) {
+        } else if (modelUtils.isLongSchema(p)) {
             Long def = (Long) p.getDefault();
             out = def == null ? out : def.toString() + "L";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             String s = inner == null ? "Object" : getTypeDeclaration(inner);
             out = String.format(Locale.ROOT, "new Map<String, %s>()", s);
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 String def = p.getDefault().toString();
                 if (def != null) {
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AspNetCoreServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AspNetCoreServerCodegen.java
index 6c882ca07ee..ba7009ea99f 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AspNetCoreServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/AspNetCoreServerCodegen.java
@@ -450,7 +450,7 @@ public class AspNetCoreServerCodegen extends AbstractCSharpCodegen {
     @Override
     public String getNullableType(Schema p, String type) {
         if (languageSpecificPrimitives.contains(type)) {
-            if (isSupportNullable() && ModelUtils.isNullable(p) && nullableType.contains(type)) {
+            if (isSupportNullable() && modelUtils.isNullable(p) && nullableType.contains(type)) {
                 return type + "?";
             } else {
                 return type;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/BashClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/BashClientCodegen.java
index 13c10ae2c9c..4026c75cf98 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/BashClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/BashClientCodegen.java
@@ -423,11 +423,11 @@ public class BashClientCodegen extends DefaultCodegen implements CodegenConfig {
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
@@ -619,7 +619,7 @@ public class BashClientCodegen extends DefaultCodegen implements CodegenConfig {
     @Override
     public CodegenOperation fromOperation(String path, String httpMethod,
                                           Operation operation, List<Server> servers) {
-        Map<String, Schema> definitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> definitions = modelUtils.getSchemas();
         CodegenOperation op = super.fromOperation(path, httpMethod, operation, servers);
 
         /**
@@ -663,8 +663,8 @@ public class BashClientCodegen extends DefaultCodegen implements CodegenConfig {
                  * If the operation produces Json and has nonempty example
                  * try to reformat it.
                  */
-                if (getConsumesInfo(this.openAPI, operation) != null
-                        && getConsumesInfo(this.openAPI, operation).contains("application/json")
+                if (getConsumesInfo(operation) != null
+                        && getConsumesInfo(operation).contains("application/json")
                         && definitions.get(p.dataType).getExample() != null) {
 
                     ObjectMapper mapper = new ObjectMapper();
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CLibcurlClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CLibcurlClientCodegen.java
index f64d2d99d3f..e84ef3e2f94 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CLibcurlClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CLibcurlClientCodegen.java
@@ -296,10 +296,10 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
     @Override
     public String getTypeDeclaration(Schema schema) {
         /* comment out below as we'll do it in the template instead
-        if (ModelUtils.isArraySchema(schema)) {
+        if (modelUtils.isArraySchema(schema)) {
             Schema inner = ((ArraySchema) schema).getItems();
             return getSchemaType(schema) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(schema)) {
+        } else if (modelUtils.isMapSchema(schema)) {
             Schema inner = (Schema) schema.getAdditionalProperties();
             return getSchemaType(schema) + "<String, " + getTypeDeclaration(inner) + ">";
         }
@@ -310,11 +310,11 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isIntegerSchema(p) || ModelUtils.isNumberSchema(p) || ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isIntegerSchema(p) || modelUtils.isNumberSchema(p) || modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "'" + escapeText((String) p.getDefault()) + "'";
             }
@@ -327,17 +327,17 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
     public String toExampleValue(Schema schema) {
         String example = super.toExampleValue(schema);
 
-        if (ModelUtils.isNullType(schema) && null != example) {
+        if (modelUtils.isNullType(schema) && null != example) {
             // The 'null' type is allowed in OAS 3.1 and above. It is not supported by OAS 3.0.x,
             // though this tooling supports it.
             return "NULL";
         }
         // correct "&#39;"s into "'"s after toString()
-        if (ModelUtils.isStringSchema(schema) && schema.getDefault() != null) {
+        if (modelUtils.isStringSchema(schema) && schema.getDefault() != null) {
             example = (String) schema.getDefault();
         }
         if (StringUtils.isNotBlank(example) && !"null".equals(example)) {
-            if (ModelUtils.isStringSchema(schema)) {
+            if (modelUtils.isStringSchema(schema)) {
                 example = "\"" + example + "\"";
             }
             return example;
@@ -346,7 +346,7 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
         if (schema.getEnum() != null && !schema.getEnum().isEmpty()) {
             // Enum case:
             example = schema.getEnum().get(0).toString();
-/*            if (ModelUtils.isStringSchema(schema)) {
+/*            if (modelUtils.isStringSchema(schema)) {
                 example = "'" + escapeText(example) + "'";
             }*/
             if (null == example)
@@ -355,8 +355,8 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
             return example;
         } else if (null != schema.get$ref()) {
             // $ref case:
-            Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
-            String ref = ModelUtils.getSimpleRef(schema.get$ref());
+            Map<String, Schema> allDefinitions = modelUtils.getSchemas();
+            String ref = modelUtils.getSimpleRef(schema.get$ref());
             if (allDefinitions != null) {
                 Schema refSchema = allDefinitions.get(ref);
                 if (null == refSchema) {
@@ -372,18 +372,18 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
                 LOGGER.warn("allDefinitions not defined in toExampleValue!\n");
             }
         }
-        if (ModelUtils.isDateSchema(schema)) {
+        if (modelUtils.isDateSchema(schema)) {
             example = "\"2013-10-20\"";
             return example;
-        } else if (ModelUtils.isDateTimeSchema(schema)) {
+        } else if (modelUtils.isDateTimeSchema(schema)) {
             example = "\"2013-10-20T19:20:30+01:00\"";
             return example;
-        } else if (ModelUtils.isBinarySchema(schema)) {
+        } else if (modelUtils.isBinarySchema(schema)) {
             example = "instantiate_binary_t(\"blah\", 5)";
             return example;
-        } else if (ModelUtils.isByteArraySchema(schema)) {
+        } else if (modelUtils.isByteArraySchema(schema)) {
             example = "YQ==";
-        } else if (ModelUtils.isStringSchema(schema)) {
+        } else if (modelUtils.isStringSchema(schema)) {
             // decimal (type: string, format: decimal)
             if ("number".equalsIgnoreCase(schema.getFormat())) {
                 return "1";
@@ -398,29 +398,29 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
             example = "";
             for (int i = 0; i < len; i++)
                 example += i;
-        } else if (ModelUtils.isIntegerSchema(schema)) {
+        } else if (modelUtils.isIntegerSchema(schema)) {
             if (schema.getMinimum() != null)
                 example = schema.getMinimum().toString();
             else
                 example = "56";
-        } else if (ModelUtils.isNumberSchema(schema)) {
+        } else if (modelUtils.isNumberSchema(schema)) {
             if (schema.getMinimum() != null)
                 example = schema.getMinimum().toString();
             else
                 example = "1.337";
-        } else if (ModelUtils.isBooleanSchema(schema)) {
+        } else if (modelUtils.isBooleanSchema(schema)) {
             example = "1";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             example = "list_create()";
-        } else if (ModelUtils.isMapSchema(schema)) {
+        } else if (modelUtils.isMapSchema(schema)) {
             example = "list_create()";
-        } else if (ModelUtils.isObjectSchema(schema)) {
+        } else if (modelUtils.isObjectSchema(schema)) {
             return null; // models are managed at moustache level
         } else {
             LOGGER.warn("Type " + schema.getType() + " not handled properly in toExampleValue");
         }
 
-        if (ModelUtils.isStringSchema(schema)) {
+        if (modelUtils.isStringSchema(schema)) {
             example = "\"" + escapeText(example) + "\"";
         }
 
@@ -744,7 +744,7 @@ public class CLibcurlClientCodegen extends DefaultCodegen implements CodegenConf
     @Override
     public CodegenProperty fromProperty(String name, Schema p) {
         CodegenProperty cm = super.fromProperty(name, p);
-        Schema ref = ModelUtils.getReferencedSchema(openAPI, p);
+        Schema ref = modelUtils.getReferencedSchema(p);
         if (ref != null) {
             if (ref.getEnum() != null) {
                 cm.isEnum = true;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java
index 9b8117a8fd7..4879d0bcff1 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpClientCodegen.java
@@ -588,7 +588,7 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
 
     @Override
     public CodegenModel fromModel(String name, Schema model) {
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel codegenModel = super.fromModel(name, model);
         if (allDefinitions != null && codegenModel != null && codegenModel.parent != null) {
             final Schema parentModel = allDefinitions.get(toModelName(codegenModel.parent));
@@ -965,14 +965,14 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
      */
     @Override
     public String toInstantiationType(Schema schema) {
-        if (ModelUtils.isMapSchema(schema)) {
+        if (modelUtils.isMapSchema(schema)) {
             Schema additionalProperties = getAdditionalProperties(schema);
             String inner = getSchemaType(additionalProperties);
-            if (ModelUtils.isMapSchema(additionalProperties)) {
+            if (modelUtils.isMapSchema(additionalProperties)) {
                 inner = toInstantiationType(additionalProperties);
             }
             return instantiationTypes.get("map") + "<String, " + inner + ">";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             ArraySchema arraySchema = (ArraySchema) schema;
             String inner = getSchemaType(arraySchema.getItems());
             return instantiationTypes.get("array") + "<" + inner + ">";
@@ -984,7 +984,7 @@ public class CSharpClientCodegen extends AbstractCSharpCodegen {
     @Override
     public String getNullableType(Schema p, String type) {
         if (languageSpecificPrimitives.contains(type)) {
-            if (isSupportNullable() && ModelUtils.isNullable(p) && nullableType.contains(type)) {
+            if (isSupportNullable() && modelUtils.isNullable(p) && nullableType.contains(type)) {
                 return type + "?";
             } else {
                 return type;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNancyFXServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNancyFXServerCodegen.java
index 93c2d0d2136..f862b31437e 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNancyFXServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNancyFXServerCodegen.java
@@ -51,7 +51,7 @@ public class CSharpNancyFXServerCodegen extends AbstractCSharpCodegen {
     private static final String PACKAGE_CONTEXT = "packageContext";
     private static final String ASYNC_SERVER = "asyncServer";
 
-    private static final Map<String, Predicate<Schema>> propertyToOpenAPITypeMapping =
+    private final Map<String, Predicate<Schema>> propertyToOpenAPITypeMapping =
             createPropertyToOpenAPITypeMapping();
 
     private String packageGuid = "{" + randomUUID().toString().toUpperCase(Locale.ROOT) + "}";
@@ -270,7 +270,7 @@ public class CSharpNancyFXServerCodegen extends AbstractCSharpCodegen {
     private void postProcessParentModels(final Map<String, Object> models) {
         LOGGER.debug("Processing parents:  " + parentModels);
         for (final String parent : parentModels) {
-            final CodegenModel parentModel = ModelUtils.getModelByName(parent, models);
+            final CodegenModel parentModel = modelUtils.getModelByName(parent, models);
             if (parentModel != null) {
                 parentModel.hasChildren = true;
                 final Collection<CodegenModel> childrenModels = childrenByParent.get(parent);
@@ -397,17 +397,17 @@ public class CSharpNancyFXServerCodegen extends AbstractCSharpCodegen {
         return super.getSchemaType(property);
     }
 
-    private static Map<String, Predicate<Schema>> createPropertyToOpenAPITypeMapping() {
+    private Map<String, Predicate<Schema>> createPropertyToOpenAPITypeMapping() {
         final ImmutableMap.Builder<String, Predicate<Schema>> mapping = ImmutableMap.builder();
         mapping.put("time", timeProperty());
         return mapping.build();
     }
 
-    private static Predicate<Schema> timeProperty() {
+    private Predicate<Schema> timeProperty() {
         return new Predicate<Schema>() {
             @Override
             public boolean apply(Schema property) {
-                return ModelUtils.isStringSchema(property) && "time".equalsIgnoreCase(property.getFormat());
+                return modelUtils.isStringSchema(property) && "time".equalsIgnoreCase(property.getFormat());
             }
         };
     }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java
index b2136e16593..c64f7105cdf 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CSharpNetCoreClientCodegen.java
@@ -306,7 +306,7 @@ public class CSharpNetCoreClientCodegen extends AbstractCSharpCodegen {
 
     @Override
     public CodegenModel fromModel(String name, Schema model) {
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel codegenModel = super.fromModel(name, model);
         if (allDefinitions != null && codegenModel != null && codegenModel.parent != null) {
             final Schema parentModel = allDefinitions.get(toModelName(codegenModel.parent));
@@ -401,7 +401,7 @@ public class CSharpNetCoreClientCodegen extends AbstractCSharpCodegen {
     @Override
     public String getNullableType(Schema p, String type) {
         if (languageSpecificPrimitives.contains(type)) {
-            if (isSupportNullable() && ModelUtils.isNullable(p) && nullableType.contains(type)) {
+            if (isSupportNullable() && modelUtils.isNullable(p) && nullableType.contains(type)) {
                 return type + "?";
             } else {
                 return type;
@@ -968,14 +968,14 @@ public class CSharpNetCoreClientCodegen extends AbstractCSharpCodegen {
      */
     @Override
     public String toInstantiationType(Schema schema) {
-        if (ModelUtils.isMapSchema(schema)) {
+        if (modelUtils.isMapSchema(schema)) {
             Schema additionalProperties = getAdditionalProperties(schema);
             String inner = getSchemaType(additionalProperties);
-            if (ModelUtils.isMapSchema(additionalProperties)) {
+            if (modelUtils.isMapSchema(additionalProperties)) {
                 inner = toInstantiationType(additionalProperties);
             }
             return instantiationTypes.get("map") + "<String, " + inner + ">";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             ArraySchema arraySchema = (ArraySchema) schema;
             String inner = getSchemaType(arraySchema.getItems());
             return instantiationTypes.get("array") + "<" + inner + ">";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ClojureClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ClojureClientCodegen.java
index 5af22a8d3f8..990c4bae7ea 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ClojureClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ClojureClientCodegen.java
@@ -168,7 +168,7 @@ public class ClojureClientCodegen extends DefaultCodegen implements CodegenConfi
             Schema inner = ap.getItems();
 
             return "(s/coll-of " + getTypeDeclaration(inner) + ")";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = (Schema) p.getAdditionalProperties();
 
             return "(s/map-of string? " + getTypeDeclaration(inner) + ")";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ConfluenceWikiCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ConfluenceWikiCodegen.java
index c2cadfa1702..523514df9e3 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ConfluenceWikiCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ConfluenceWikiCodegen.java
@@ -102,11 +102,11 @@ public class ConfluenceWikiCodegen extends DefaultCodegen implements CodegenConf
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppPistacheServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppPistacheServerCodegen.java
index 6cd08e70a42..589e6b5c0bb 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppPistacheServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppPistacheServerCodegen.java
@@ -229,7 +229,7 @@ public class CppPistacheServerCodegen extends AbstractCppCodegen {
             ApiResponse apiResponse = findMethodResponse(operation.getResponses());
 
             if (apiResponse != null) {
-                Schema response = ModelUtils.getSchemaFromResponse(apiResponse);
+                Schema response = modelUtils.getSchemaFromResponse(apiResponse);
                 if (response != null) {
                     CodegenProperty cm = fromProperty("response", response);
                     op.vendorExtensions.put("x-codegen-response", cm);
@@ -350,20 +350,20 @@ public class CppPistacheServerCodegen extends AbstractCppCodegen {
     public String getTypeDeclaration(Schema p) {
         String openAPIType = getSchemaType(p);
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
         }
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "<std::string, " + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isByteArraySchema(p)) {
+        } else if (modelUtils.isByteArraySchema(p)) {
             return "std::string";
         }
-        if (ModelUtils.isStringSchema(p)
-                || ModelUtils.isDateSchema(p)
-                || ModelUtils.isDateTimeSchema(p) || ModelUtils.isFileSchema(p)
+        if (modelUtils.isStringSchema(p)
+                || modelUtils.isDateSchema(p)
+                || modelUtils.isDateTimeSchema(p) || modelUtils.isFileSchema(p)
                 || languageSpecificPrimitives.contains(openAPIType)) {
             return toModelName(openAPIType);
         }
@@ -373,34 +373,34 @@ public class CppPistacheServerCodegen extends AbstractCppCodegen {
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return "false";
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return "\"\"";
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return "\"\"";
-        } else if (ModelUtils.isNumberSchema(p)) {
-            if (ModelUtils.isFloatSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
+            if (modelUtils.isFloatSchema(p)) {
                 return "0.0f";
             }
             return "0.0";
-        } else if (ModelUtils.isIntegerSchema(p)) {
-            if (ModelUtils.isLongSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
+            if (modelUtils.isLongSchema(p)) {
                 return "0L";
             }
             return "0";
-        } else if (ModelUtils.isByteArraySchema(p)) {
+        } else if (modelUtils.isByteArraySchema(p)) {
             return "\"\"";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
             return "std::map<std::string, " + inner + ">()";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
             return "std::vector<" + inner + ">()";
         } else if (!StringUtils.isEmpty(p.get$ref())) { // model
-            return toModelName(ModelUtils.getSimpleRef(p.get$ref())) + "()";
-        } else if (ModelUtils.isStringSchema(p)) {
+            return toModelName(modelUtils.getSimpleRef(p.get$ref())) + "()";
+        } else if (modelUtils.isStringSchema(p)) {
             return "\"\"";
         }
 
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppQt5AbstractCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppQt5AbstractCodegen.java
index c3227182214..15916b6942c 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppQt5AbstractCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppQt5AbstractCodegen.java
@@ -181,16 +181,16 @@ public class CppQt5AbstractCodegen extends AbstractCppCodegen implements Codegen
     public String getTypeDeclaration(Schema p) {
         String openAPIType = getSchemaType(p);
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "<QString, " + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isBinarySchema(p)) {
+        } else if (modelUtils.isBinarySchema(p)) {
             return getSchemaType(p);
-        } else if (ModelUtils.isFileSchema(p)) {
+        } else if (modelUtils.isFileSchema(p)) {
             return getSchemaType(p);
         }
         if (foundationClasses.contains(openAPIType)) {
@@ -205,33 +205,33 @@ public class CppQt5AbstractCodegen extends AbstractCppCodegen implements Codegen
     @Override
     @SuppressWarnings("rawtypes")
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return "false";
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return "NULL";
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return "NULL";
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (SchemaTypeUtil.FLOAT_FORMAT.equals(p.getFormat())) {
                 return "0.0f";
             }
             return "0.0";
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (SchemaTypeUtil.INTEGER64_FORMAT.equals(p.getFormat())) {
                 return "0L";
             }
             return "0";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "QMap<QString, " + getTypeDeclaration(inner) + ">()";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "QList<" + getTypeDeclaration(inner) + ">()";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             return "QString(\"\")";
         } else if (!StringUtils.isEmpty(p.get$ref())) {
-            return toModelName(ModelUtils.getSimpleRef(p.get$ref())) + "()";
+            return toModelName(modelUtils.getSimpleRef(p.get$ref())) + "()";
         }
         return "NULL";
     }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestSdkClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestSdkClientCodegen.java
index 72605513a34..1a681538eaa 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestSdkClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestSdkClientCodegen.java
@@ -27,7 +27,6 @@ import io.swagger.v3.oas.models.servers.Server;
 import org.apache.commons.lang3.StringUtils;
 import org.openapitools.codegen.*;
 import org.openapitools.codegen.meta.features.*;
-import org.openapitools.codegen.utils.ModelUtils;
 
 import java.util.*;
 
@@ -271,8 +270,8 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
             ApiResponse methodResponse = findMethodResponse(operation.getResponses());
 
             if (methodResponse != null) {
-                Schema response = ModelUtils.getSchemaFromResponse(methodResponse);
-                response = ModelUtils.unaliasSchema(this.openAPI, response, importMapping);
+                Schema response = modelUtils.getSchemaFromResponse(methodResponse);
+                response = modelUtils.unaliasSchema(response, importMapping);
                 if (response != null) {
                     CodegenProperty cm = fromProperty("response", response);
                     op.vendorExtensions.put("x-codegen-response", cm);
@@ -344,18 +343,18 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
     public String getTypeDeclaration(Schema p) {
         String openAPIType = getSchemaType(p);
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "<utility::string_t, " + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isFileSchema(p) || ModelUtils.isBinarySchema(p)) {
+        } else if (modelUtils.isFileSchema(p) || modelUtils.isBinarySchema(p)) {
             return "std::shared_ptr<" + openAPIType + ">";
-        } else if (ModelUtils.isStringSchema(p)
-                || ModelUtils.isDateSchema(p) || ModelUtils.isDateTimeSchema(p)
-                || ModelUtils.isFileSchema(p) || ModelUtils.isUUIDSchema(p)
+        } else if (modelUtils.isStringSchema(p)
+                || modelUtils.isDateSchema(p) || modelUtils.isDateTimeSchema(p)
+                || modelUtils.isFileSchema(p) || modelUtils.isUUIDSchema(p)
                 || languageSpecificPrimitives.contains(openAPIType)) {
             return toModelName(openAPIType);
         }
@@ -365,26 +364,26 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return "false";
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return "utility::datetime()";
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return "utility::datetime()";
-        } else if (ModelUtils.isNumberSchema(p)) {
-            if (ModelUtils.isFloatSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
+            if (modelUtils.isFloatSchema(p)) {
                 return "0.0f";
             }
             return "0.0";
-        } else if (ModelUtils.isIntegerSchema(p)) {
-            if (ModelUtils.isLongSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
+            if (modelUtils.isLongSchema(p)) {
                 return "0L";
             }
             return "0";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
             return "std::map<utility::string_t, " + inner + ">()";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
             if (!languageSpecificPrimitives.contains(inner)) {
@@ -392,10 +391,10 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
             }
             return "std::vector<" + inner + ">()";
         } else if (!StringUtils.isEmpty(p.get$ref())) {
-            return "new " + toModelName(ModelUtils.getSimpleRef(p.get$ref())) + "()";
-        } else if (ModelUtils.isStringSchema(p)) {
+            return "new " + toModelName(modelUtils.getSimpleRef(p.get$ref())) + "()";
+        } else if (modelUtils.isStringSchema(p)) {
             return "utility::conversions::to_string_t(\"\")";
-        } else if (ModelUtils.isFreeFormObject(openAPI, p)) {
+        } else if (modelUtils.isFreeFormObject(p)) {
             return "new Object()";
         }
 
@@ -446,7 +445,7 @@ public class CppRestSdkClientCodegen extends AbstractCppCodegen {
 
     private void postProcessParentModels(final Map<String, Object> models) {
         for (final String parent : parentModels) {
-            final CodegenModel parentModel = ModelUtils.getModelByName(parent, models);
+            final CodegenModel parentModel = modelUtils.getModelByName(parent, models);
             final Collection<CodegenModel> childrenModels = childrenByParent.get(parent);
             for (final CodegenModel child : childrenModels) {
                 processParentPropertiesInChildModel(parentModel, child);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestbedServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestbedServerCodegen.java
index f710e3a6588..3e219094515 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestbedServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppRestbedServerCodegen.java
@@ -345,18 +345,18 @@ public class CppRestbedServerCodegen extends AbstractCppCodegen {
     public String getTypeDeclaration(Schema p) {
         String openAPIType = getSchemaType(p);
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "<std::string, " + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isByteArraySchema(p)) {
+        } else if (modelUtils.isByteArraySchema(p)) {
             return "std::string";
-        } else if (ModelUtils.isStringSchema(p)
-                || ModelUtils.isDateSchema(p)
-                || ModelUtils.isDateTimeSchema(p) || ModelUtils.isFileSchema(p)
+        } else if (modelUtils.isStringSchema(p)
+                || modelUtils.isDateSchema(p)
+                || modelUtils.isDateTimeSchema(p) || modelUtils.isFileSchema(p)
                 || languageSpecificPrimitives.contains(openAPIType)) {
             return toModelName(openAPIType);
         }
@@ -366,32 +366,32 @@ public class CppRestbedServerCodegen extends AbstractCppCodegen {
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isStringSchema(p)) {
+        if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             } else {
                 return "\"\"";
             }
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             } else {
                 return "false";
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             } else {
                 return "\"\"";
             }
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             } else {
                 return "\"\"";
             }
-        } else if (ModelUtils.isNumberSchema(p)) {
-            if (ModelUtils.isFloatSchema(p)) { // float
+        } else if (modelUtils.isNumberSchema(p)) {
+            if (modelUtils.isFloatSchema(p)) { // float
                 if (p.getDefault() != null) {
                     return p.getDefault().toString() + "f";
                 } else {
@@ -404,8 +404,8 @@ public class CppRestbedServerCodegen extends AbstractCppCodegen {
                     return "0.0";
                 }
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
-            if (ModelUtils.isLongSchema(p)) { // long
+        } else if (modelUtils.isIntegerSchema(p)) {
+            if (modelUtils.isLongSchema(p)) { // long
                 if (p.getDefault() != null) {
                     return p.getDefault().toString() + "L";
                 } else {
@@ -418,16 +418,16 @@ public class CppRestbedServerCodegen extends AbstractCppCodegen {
                     return "0";
                 }
             }
-        } else if (ModelUtils.isByteArraySchema(p)) {
+        } else if (modelUtils.isByteArraySchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             } else {
                 return "\"\"";
             }
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
             return "std::map<std::string, " + inner + ">()";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
             if (!languageSpecificPrimitives.contains(inner)) {
@@ -435,7 +435,7 @@ public class CppRestbedServerCodegen extends AbstractCppCodegen {
             }
             return "std::vector<" + inner + ">()";
         } else if (!StringUtils.isEmpty(p.get$ref())) {
-            return "std::make_shared<" + toModelName(ModelUtils.getSimpleRef(p.get$ref())) + ">()";
+            return "std::make_shared<" + toModelName(modelUtils.getSimpleRef(p.get$ref())) + ">()";
         }
 
         return "nullptr";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppTizenClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppTizenClientCodegen.java
index 16bd058996f..c278d43805e 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppTizenClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppTizenClientCodegen.java
@@ -161,9 +161,9 @@ public class CppTizenClientCodegen extends AbstractCppCodegen implements Codegen
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             return instantiationTypes.get("map");
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             return instantiationTypes.get("array");
         } else {
             return null;
@@ -232,28 +232,28 @@ public class CppTizenClientCodegen extends AbstractCppCodegen implements Codegen
     //Might not be needed
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return "bool(false)";
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (SchemaTypeUtil.FLOAT_FORMAT.equals(p.getFormat())) {
                 return "float(0)";
             }
             return "double(0)";
 
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (SchemaTypeUtil.INTEGER64_FORMAT.equals(p.getFormat())) {
                 return "long(0)";
             }
             return "int(0)";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             return "new std::map()";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             return "new std::list()";
         } else if (!StringUtils.isEmpty(p.get$ref())) {
-            return "new " + toModelName(ModelUtils.getSimpleRef(p.get$ref())) + "()";
-        } else if (ModelUtils.isDateSchema(p) || ModelUtils.isDateTimeSchema(p)) {
+            return "new " + toModelName(modelUtils.getSimpleRef(p.get$ref())) + "()";
+        } else if (modelUtils.isDateSchema(p) || modelUtils.isDateTimeSchema(p)) {
             return "null";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             return "std::string()";
         }
         return "null";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppUE4ClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppUE4ClientCodegen.java
index c0a1175bb64..828c95d1be2 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppUE4ClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/CppUE4ClientCodegen.java
@@ -379,11 +379,11 @@ public class CppUE4ClientCodegen extends AbstractCppCodegen {
     public String getTypeDeclaration(Schema p) {
         String openAPIType = getSchemaType(p);
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
             return getSchemaType(p) + "<FString, " + getTypeDeclaration(inner) + ">";
         }
@@ -404,41 +404,41 @@ public class CppUE4ClientCodegen extends AbstractCppCodegen {
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isStringSchema(p)) {
+        if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "TEXT(\"" + p.getDefault().toString() + "\")";
             } else {
                 return null;
             }
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             } else {
                 return "false";
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return "FDateTime(0)";
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return "FDateTime(0)";
-        } else if (ModelUtils.isDoubleSchema(p)) {
+        } else if (modelUtils.isDoubleSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             } else {
                 return "0.0";
             }
-        } else if (ModelUtils.isFloatSchema(p)) {
+        } else if (modelUtils.isFloatSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             } else {
                 return "0.0f";
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             } else {
                 return "0";
             }
-        } else if (ModelUtils.isLongSchema(p)) {
+        } else if (modelUtils.isLongSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             } else {
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartClientCodegen.java
index d06f3019c57..9d7563c4c36 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartClientCodegen.java
@@ -412,14 +412,14 @@ public class DartClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toDefaultValue(Schema schema) {
-        if (ModelUtils.isMapSchema(schema)) {
+        if (modelUtils.isMapSchema(schema)) {
             return "const {}";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             return "const []";
         }
 
         if (schema.getDefault() != null) {
-            if (ModelUtils.isStringSchema(schema)) {
+            if (modelUtils.isStringSchema(schema)) {
                 return "'" + schema.getDefault().toString().replaceAll("'", "\\'") + "'";
             }
             return schema.getDefault().toString();
@@ -430,11 +430,11 @@ public class DartClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
 
             return getSchemaType(p) + "<String, " + getTypeDeclaration(inner) + ">";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartDioClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartDioClientCodegen.java
index 2d0a3ae0cb7..5f31781df6d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartDioClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartDioClientCodegen.java
@@ -118,14 +118,14 @@ public class DartDioClientCodegen extends DartClientCodegen {
 
     @Override
     public String toDefaultValue(Schema schema) {
-        if (ModelUtils.isMapSchema(schema)) {
+        if (modelUtils.isMapSchema(schema)) {
             return "const {}";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             return "const []";
         }
 
         if (schema.getDefault() != null) {
-            if (ModelUtils.isStringSchema(schema)) {
+            if (modelUtils.isStringSchema(schema)) {
                 return "'" + schema.getDefault().toString().replaceAll("'", "\\'") + "'";
             }
             return schema.getDefault().toString();
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartJaguarClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartJaguarClientCodegen.java
index d932c346a4f..02ab36627e4 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartJaguarClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/DartJaguarClientCodegen.java
@@ -132,14 +132,14 @@ public class DartJaguarClientCodegen extends DartClientCodegen {
 
     @Override
     public String toDefaultValue(Schema schema) {
-        if (ModelUtils.isMapSchema(schema)) {
+        if (modelUtils.isMapSchema(schema)) {
             return "const {}";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             return "const []";
         }
 
         if (schema.getDefault() != null) {
-            if (ModelUtils.isStringSchema(schema)) {
+            if (modelUtils.isStringSchema(schema)) {
                 return "'" + schema.getDefault().toString().replaceAll("'", "\\'") + "'";
             }
             return schema.getDefault().toString();
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java
index 728db0d2152..86e47f6723d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElixirClientCodegen.java
@@ -490,42 +490,42 @@ public class ElixirClientCodegen extends DefaultCodegen implements CodegenConfig
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "%{optional(String.t) => " + getTypeDeclaration(inner) + "}";
-        } else if (ModelUtils.isPasswordSchema(p)) {
+        } else if (modelUtils.isPasswordSchema(p)) {
             return "String.t";
-        } else if (ModelUtils.isEmailSchema(p)) {
+        } else if (modelUtils.isEmailSchema(p)) {
             return "String.t";
-        } else if (ModelUtils.isByteArraySchema(p)) {
+        } else if (modelUtils.isByteArraySchema(p)) {
             return "binary()";
-        } else if (ModelUtils.isUUIDSchema(p)) {
+        } else if (modelUtils.isUUIDSchema(p)) {
             return "String.t";
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return "Date.t";
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return "DateTime.t";
-        } else if (ModelUtils.isObjectSchema(p)) {
+        } else if (modelUtils.isObjectSchema(p)) {
             // TODO How to map it?
             return super.getTypeDeclaration(p);
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             return "integer()";
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             return "float()";
-        } else if (ModelUtils.isBinarySchema(p) || ModelUtils.isFileSchema(p)) {
+        } else if (modelUtils.isBinarySchema(p) || modelUtils.isFileSchema(p)) {
             return "String.t";
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             return "boolean()";
         } else if (!StringUtils.isEmpty(p.get$ref())) { // model
             // How to map it?
             return super.getTypeDeclaration(p);
-        } else if (ModelUtils.isFileSchema(p)) {
+        } else if (modelUtils.isFileSchema(p)) {
             return "String.t";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             return "String.t";
         }
         return super.getTypeDeclaration(p);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElmClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElmClientCodegen.java
index 191b26445d3..dcc182e4d42 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElmClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ElmClientCodegen.java
@@ -238,7 +238,7 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
             return instantiationTypes.get("array") + " " + inner;
@@ -414,19 +414,19 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
     
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isStringSchema(p)) {
+        if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + p.getDefault().toString() + "\"";
             }
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return Boolean.valueOf(p.getDefault().toString()) ? "True" : "False";
             }
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
@@ -450,11 +450,11 @@ public class ElmClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner);
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getTypeDeclaration(inner);
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ErlangProperCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ErlangProperCodegen.java
index 5959d6e79a8..e67952b4e58 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ErlangProperCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ErlangProperCodegen.java
@@ -137,7 +137,7 @@ public class ErlangProperCodegen extends DefaultCodegen implements CodegenConfig
     @Override
     public CodegenModel fromModel(String name, Schema model) {
         CodegenModel cm = super.fromModel(name, model);
-        if(ModelUtils.isArraySchema(model)) {
+        if(modelUtils.isArraySchema(model)) {
             return new CodegenArrayModel(cm, (ArraySchema) model);
         } else {
             return cm;
@@ -152,7 +152,7 @@ public class ErlangProperCodegen extends DefaultCodegen implements CodegenConfig
     @Override
     public String getTypeDeclaration(Schema schema) {
         String typeDeclaration = super.getSchemaType(schema);
-        if(ModelUtils.isArraySchema(schema)) {
+        if(modelUtils.isArraySchema(schema)) {
             ArraySchema arraySchema = (ArraySchema) schema;
             String complexType = getSchemaType(arraySchema.getItems());
 
@@ -170,7 +170,7 @@ public class ErlangProperCodegen extends DefaultCodegen implements CodegenConfig
     @Override
     public String getSchemaType(Schema schema) {
         String schemaType = super.getSchemaType(schema);
-        if(ModelUtils.isArraySchema(schema)) {
+        if(modelUtils.isArraySchema(schema)) {
             ArraySchema arraySchema = (ArraySchema) schema;
             String complexType = getSchemaType(arraySchema.getItems());
 
@@ -183,7 +183,7 @@ public class ErlangProperCodegen extends DefaultCodegen implements CodegenConfig
             if(minItems != null && maxItems != null) sb.append(", ").append(maxItems);
 
             return sb.append(")").toString();
-        } else if(ModelUtils.isIntegerSchema(schema)) {
+        } else if(modelUtils.isIntegerSchema(schema)) {
             StringBuilder sb = new StringBuilder("integer(");
 
             BigDecimal min = schema.getMinimum();
@@ -192,9 +192,9 @@ public class ErlangProperCodegen extends DefaultCodegen implements CodegenConfig
             if(min != null && max != null) sb.append(", ").append(max);
 
             return sb.append(")").toString();
-        } else if(ModelUtils.isDateSchema(schema) || ModelUtils.isDateTimeSchema(schema)) {
+        } else if(modelUtils.isDateSchema(schema) || modelUtils.isDateTimeSchema(schema)) {
             return typeMapping.get(schemaType);
-        } else if(ModelUtils.isStringSchema(schema)) {
+        } else if(modelUtils.isStringSchema(schema)) {
             StringBuilder sb = new StringBuilder("binary(");
             Integer min = schema.getMinLength();
             Integer max = schema.getMaxLength();
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/FlashClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/FlashClientCodegen.java
index 4f419053723..1af68a1690c 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/FlashClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/FlashClientCodegen.java
@@ -235,7 +235,7 @@ public class FlashClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p) || ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isArraySchema(p) || modelUtils.isMapSchema(p)) {
             return getSchemaType(p);
         }
         return super.getTypeDeclaration(p);
@@ -258,27 +258,27 @@ public class FlashClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return "false";
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return "null";
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return "null";
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return "0.0";
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return "0";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             return "new Dictionary()";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             return "new Array()";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             return "null";
         } else {
             return "NaN";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoClientCodegen.java
index f91fa0f9a9a..e5ea237d7bf 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GoClientCodegen.java
@@ -349,8 +349,8 @@ public class GoClientCodegen extends AbstractGoCodegen {
 
     @Override
     public String toDefaultValue(Schema p) {
-        p = ModelUtils.getReferencedSchema(this.openAPI, p);
-        if (ModelUtils.isStringSchema(p)) {
+        p = modelUtils.getReferencedSchema(p);
+        if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + escapeText((String) p.getDefault()) + "\"";
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GraphQLNodeJSExpressServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GraphQLNodeJSExpressServerCodegen.java
index 736d98d71d3..4bd5273a732 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GraphQLNodeJSExpressServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/GraphQLNodeJSExpressServerCodegen.java
@@ -123,7 +123,7 @@ public class GraphQLNodeJSExpressServerCodegen extends AbstractGraphQLCodegen im
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
 
@@ -131,7 +131,7 @@ public class GraphQLNodeJSExpressServerCodegen extends AbstractGraphQLCodegen im
             // between some specific types for GraphQL:
             // return "[" + getTypeDeclaration(inner) + "]";
             return getTypeDeclaration(inner);
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = (Schema) p.getAdditionalProperties();
 
             return getTypeDeclaration(inner);
@@ -139,7 +139,7 @@ public class GraphQLNodeJSExpressServerCodegen extends AbstractGraphQLCodegen im
 
         // IMPORANT NOTE Not using the supertype invocation, because we want to UpperCamelize the type:
         String schemaType = getSchemaType(p);
-        String nullable = ModelUtils.isNullable(p) ? "" : "!";
+        String nullable = modelUtils.isNullable(p) ? "" : "!";
 
         if (typeMapping.containsKey(schemaType)) {
             return typeMapping.get(schemaType) + nullable;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellHttpClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellHttpClientCodegen.java
index 6c58e89d6d2..47895fc1eb6 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellHttpClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellHttpClientCodegen.java
@@ -624,11 +624,11 @@ public class HaskellHttpClientCodegen extends DefaultCodegen implements CodegenC
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "(Map.Map String " + getTypeDeclaration(inner) + ")";
         }
@@ -650,7 +650,7 @@ public class HaskellHttpClientCodegen extends DefaultCodegen implements CodegenC
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             Schema additionalProperties2 = getAdditionalProperties(p);
             String type = additionalProperties2.getType();
             if (null == type) {
@@ -659,7 +659,7 @@ public class HaskellHttpClientCodegen extends DefaultCodegen implements CodegenC
             }
             String inner = getSchemaType(additionalProperties2);
             return "(Map.Map Text " + inner + ")";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             return getSchemaType(ap.getItems());
         } else {
@@ -1245,11 +1245,11 @@ public class HaskellHttpClientCodegen extends DefaultCodegen implements CodegenC
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isStringSchema(p)) {
+        if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + escapeText((String) p.getDefault()) + "\"";
             }
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 if (p.getDefault().toString().equalsIgnoreCase("false"))
                     return "False";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellServantCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellServantCodegen.java
index 6181b572f2e..9d068c4c649 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellServantCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/HaskellServantCodegen.java
@@ -368,11 +368,11 @@ public class HaskellServantCodegen extends DefaultCodegen implements CodegenConf
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "(Map.Map String " + getTypeDeclaration(inner) + ")";
         }
@@ -407,7 +407,7 @@ public class HaskellServantCodegen extends DefaultCodegen implements CodegenConf
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             Schema additionalProperties2 = getAdditionalProperties(p);
             String type = additionalProperties2.getType();
             if (null == type) {
@@ -416,7 +416,7 @@ public class HaskellServantCodegen extends DefaultCodegen implements CodegenConf
             }
             String inner = getSchemaType(additionalProperties2);
             return "(Map.Map Text " + inner + ")";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
             // Return only the inner type; the wrapping with QueryList is done
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JMeterClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JMeterClientCodegen.java
index 9678d29c880..fb0dc35efc9 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JMeterClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JMeterClientCodegen.java
@@ -201,11 +201,11 @@ public class JMeterClientCodegen extends DefaultCodegen implements CodegenConfig
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaCXFExtServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaCXFExtServerCodegen.java
index 01b7293ab94..27a97fcfa12 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaCXFExtServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavaCXFExtServerCodegen.java
@@ -1431,9 +1431,9 @@ public class JavaCXFExtServerCodegen extends JavaCXFServerCodegen implements CXF
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isGenerateAliasAsModel(p) && StringUtils.isNotEmpty(p.get$ref())) {
-            Schema<?> ref = ModelUtils.getReferencedSchema(this.openAPI, p);
-            if (ModelUtils.isArraySchema(ref) || ModelUtils.isMapSchema(ref)) {
+        if (modelUtils.isGenerateAliasAsModel(p) && StringUtils.isNotEmpty(p.get$ref())) {
+            Schema<?> ref = modelUtils.getReferencedSchema(p);
+            if (modelUtils.isArraySchema(ref) || modelUtils.isMapSchema(ref)) {
                 String typeDeclaration = getTypeDeclaration(p);
                 return String.format(Locale.ROOT, "new %s()", typeDeclaration);
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptApolloClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptApolloClientCodegen.java
index 3476192f4c4..a9b98bd35d1 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptApolloClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptApolloClientCodegen.java
@@ -560,11 +560,11 @@ public class JavascriptApolloClientCodegen extends DefaultCodegen implements Cod
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "{String: " + getTypeDeclaration(inner) + "}";
         }
@@ -573,23 +573,23 @@ public class JavascriptApolloClientCodegen extends DefaultCodegen implements Cod
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "'" + p.getDefault() + "'";
             }
@@ -814,7 +814,7 @@ public class JavascriptApolloClientCodegen extends DefaultCodegen implements Cod
     @Override
     public CodegenModel fromModel(String name, Schema model) {
 
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel codegenModel = super.fromModel(name, model);
 
         if (allDefinitions != null && codegenModel != null && codegenModel.parent != null && codegenModel.hasEnums) {
@@ -822,14 +822,14 @@ public class JavascriptApolloClientCodegen extends DefaultCodegen implements Cod
             final CodegenModel parentCodegenModel = super.fromModel(codegenModel.parent, parentModel);
             codegenModel = JavascriptApolloClientCodegen.reconcileInlineEnums(codegenModel, parentCodegenModel);
         }
-        if (ModelUtils.isArraySchema(model)) {
+        if (modelUtils.isArraySchema(model)) {
             ArraySchema am = (ArraySchema) model;
             if (codegenModel != null && am.getItems() != null) {
                 String itemType = getSchemaType(am.getItems());
                 codegenModel.vendorExtensions.put("x-is-array", true);
                 codegenModel.vendorExtensions.put("x-item-type", itemType);
             }
-        } else if (ModelUtils.isMapSchema(model)) {
+        } else if (modelUtils.isMapSchema(model)) {
             if (codegenModel != null && getAdditionalProperties(model) != null) {
                 String itemType = getSchemaType(getAdditionalProperties(model));
                 codegenModel.vendorExtensions.put("x-is-map", true);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClientCodegen.java
index c3fa812bcab..eda56edd76b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClientCodegen.java
@@ -611,11 +611,11 @@ public class JavascriptClientCodegen extends DefaultCodegen implements CodegenCo
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "{String: " + getTypeDeclaration(inner) + "}";
         }
@@ -624,23 +624,23 @@ public class JavascriptClientCodegen extends DefaultCodegen implements CodegenCo
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "'" + p.getDefault() + "'";
             }
@@ -865,7 +865,7 @@ public class JavascriptClientCodegen extends DefaultCodegen implements CodegenCo
     @Override
     public CodegenModel fromModel(String name, Schema model) {
 
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel codegenModel = super.fromModel(name, model);
 
         if (allDefinitions != null && codegenModel != null && codegenModel.parent != null && codegenModel.hasEnums) {
@@ -873,14 +873,14 @@ public class JavascriptClientCodegen extends DefaultCodegen implements CodegenCo
             final CodegenModel parentCodegenModel = super.fromModel(codegenModel.parent, parentModel);
             codegenModel = JavascriptClientCodegen.reconcileInlineEnums(codegenModel, parentCodegenModel);
         }
-        if (ModelUtils.isArraySchema(model)) {
+        if (modelUtils.isArraySchema(model)) {
             ArraySchema am = (ArraySchema) model;
             if (codegenModel != null && am.getItems() != null) {
                 String itemType = getSchemaType(am.getItems());
                 codegenModel.vendorExtensions.put("x-is-array", true);
                 codegenModel.vendorExtensions.put("x-item-type", itemType);
             }
-        } else if (ModelUtils.isMapSchema(model)) {
+        } else if (modelUtils.isMapSchema(model)) {
             if (codegenModel != null && getAdditionalProperties(model) != null) {
                 String itemType = getSchemaType(getAdditionalProperties(model));
                 codegenModel.vendorExtensions.put("x-is-map", true);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClosureAngularClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClosureAngularClientCodegen.java
index 877db877e4d..6d050696c24 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClosureAngularClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/JavascriptClosureAngularClientCodegen.java
@@ -220,14 +220,14 @@ public class JavascriptClosureAngularClientCodegen extends DefaultCodegen implem
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "<!" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "Object<!string, "+ getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isFileSchema(p)) {
+        } else if (modelUtils.isFileSchema(p)) {
             return "Object";
         }
         String type = super.getTypeDeclaration(p);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/K6ClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/K6ClientCodegen.java
index edd71aeae55..85f3d208f19 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/K6ClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/K6ClientCodegen.java
@@ -325,16 +325,16 @@ public class K6ClientCodegen extends DefaultCodegen implements CodegenConfig {
                     }
                 }
 
-                if (hasBodyParameter(openAPI, operation) || hasFormParameter(openAPI, operation)) {
-                    String defaultContentType = hasFormParameter(openAPI, operation) ? "application/x-www-form-urlencoded" : "application/json";
-                    List<String> consumes = new ArrayList<>(getConsumesInfo(openAPI, operation));
+                if (hasBodyParameter(operation) || hasFormParameter(operation)) {
+                    String defaultContentType = hasFormParameter(operation) ? "application/x-www-form-urlencoded" : "application/json";
+                    List<String> consumes = new ArrayList<>(getConsumesInfo(operation));
                     String contentTypeValue = consumes == null || consumes.isEmpty() ? defaultContentType : consumes.get(0);
                     if (contentTypeValue.equals("*/*"))
                         contentTypeValue = "application/json";
                     Parameter contentType = new Parameter("Content-Type", getDoubleQuotedString(contentTypeValue));
                     httpParams.add(contentType);
 
-                    RequestBody requestBody = ModelUtils.getReferencedRequestBody(openAPI, operation.getRequestBody());
+                    RequestBody requestBody = modelUtils.getReferencedRequestBody(operation.getRequestBody());
 
                     for (Map.Entry<String, ApiResponse> responseEntry : operation.getResponses().entrySet()) {
                         CodegenResponse r = fromResponse(responseEntry.getKey(), responseEntry.getValue());
@@ -349,7 +349,7 @@ public class K6ClientCodegen extends DefaultCodegen implements CodegenConfig {
                     for (CodegenParameter parameter : formParameteres) {
                         String reference = "";
                         if (parameter.isModel) {
-                            Schema nestedSchema = ModelUtils.getSchema(openAPI, parameter.baseType);
+                            Schema nestedSchema = modelUtils.getSchema(parameter.baseType);
                             CodegenModel model = fromModel(parameter.paramName, nestedSchema);
                             reference = generateNestedModelTemplate(model);
                             if (parameter.dataType.equals("List")) {
@@ -369,7 +369,7 @@ public class K6ClientCodegen extends DefaultCodegen implements CodegenConfig {
                         bodyOrFormParams.add(k6Parameter);
                     }
                 }
-                String accepts = getAccept(openAPI, operation);
+                String accepts = getAccept(operation);
                 String responseType = getDoubleQuotedString(accepts);
 
                 try {
@@ -602,10 +602,10 @@ public class K6ClientCodegen extends DefaultCodegen implements CodegenConfig {
         return input.replace("*/", "*_/").replace("/*", "/_*");
     }
 
-    private static String getAccept(OpenAPI openAPI, Operation operation) {
+    private String getAccept(Operation operation) {
         String accepts = null;
         String defaultContentType = "application/json";
-        Set<String> producesInfo = getProducesInfo(openAPI, operation);
+        Set<String> producesInfo = getProducesInfo(operation);
         if (producesInfo != null && !producesInfo.isEmpty()) {
             ArrayList<String> produces = new ArrayList<>(producesInfo);
             StringBuilder sb = new StringBuilder();
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/LuaClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/LuaClientCodegen.java
index f69352db3a9..2f8fc7d6f7f 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/LuaClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/LuaClientCodegen.java
@@ -362,11 +362,11 @@ public class LuaClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner);
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getTypeDeclaration(inner);
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/NimClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/NimClientCodegen.java
index f9803661b38..7502d644cc5 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/NimClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/NimClientCodegen.java
@@ -270,14 +270,14 @@ public class NimClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             if (inner == null) {
                 return null;
             }
             return "seq[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             if (inner == null) {
                 inner = new StringSchema();
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/OCamlClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/OCamlClientCodegen.java
index c75c08053a9..971e834ceed 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/OCamlClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/OCamlClientCodegen.java
@@ -575,7 +575,7 @@ public class OCamlClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             if (inner == null) {
@@ -583,7 +583,7 @@ public class OCamlClientCodegen extends DefaultCodegen implements CodegenConfig
                 inner = new StringSchema().description("TODO default missing array inner type to string");
             }
             return getTypeDeclaration(inner) + " list";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             if (inner == null) {
                 LOGGER.warn(p.getName() + "(map property) does not have a proper inner type defined. Default to string");
@@ -596,7 +596,7 @@ public class OCamlClientCodegen extends DefaultCodegen implements CodegenConfig
             return enumUniqNames.get(h);
         }
 
-        Schema referencedSchema = ModelUtils.getReferencedSchema(openAPI, p);
+        Schema referencedSchema = modelUtils.getReferencedSchema(p);
         if (referencedSchema != null && referencedSchema.getEnum() != null) {
             String h = hashEnum(referencedSchema);
             return "Enums." + enumUniqNames.get(h);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ObjcClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ObjcClientCodegen.java
index 11d68c0771e..04e93f9364a 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ObjcClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ObjcClientCodegen.java
@@ -325,9 +325,9 @@ public class ObjcClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             return instantiationTypes.get("map");
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             return instantiationTypes.get("array");
         } else {
             return null;
@@ -366,7 +366,7 @@ public class ObjcClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             String innerTypeDeclaration = getTypeDeclaration(inner);
@@ -388,7 +388,7 @@ public class ObjcClientCodegen extends DefaultCodegen implements CodegenConfig {
                 }
                 return getSchemaType(p) + "<" + innerTypeDeclaration + ">*";
             }
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
 
             String innerTypeDeclaration = getTypeDeclaration(inner);
@@ -679,23 +679,23 @@ public class ObjcClientCodegen extends DefaultCodegen implements CodegenConfig {
      */
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isDateSchema(p)) {
+        if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return "@" + p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return "@" + p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "@\"" + (String) p.getDefault() + "\"";
             }
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 if (p.getDefault().toString().equalsIgnoreCase("false"))
                     return "@(NO)";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PerlClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PerlClientCodegen.java
index 16c360a7ba8..c25a9700c18 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PerlClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PerlClientCodegen.java
@@ -252,11 +252,11 @@ public class PerlClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[string," + getTypeDeclaration(inner) + "]";
         }
@@ -283,23 +283,23 @@ public class PerlClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "'" + p.getDefault() + "'";
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSilexServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSilexServerCodegen.java
index 3c33950a034..dba4a19bdb1 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSilexServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSilexServerCodegen.java
@@ -171,11 +171,11 @@ public class PhpSilexServerCodegen extends DefaultCodegen implements CodegenConf
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[string," + getTypeDeclaration(inner) + "]";
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
index 30c41f7f291..2f29fa6d3d2 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpSymfonyServerCodegen.java
@@ -536,13 +536,13 @@ public class PhpSymfonyServerCodegen extends AbstractPhpCodegen implements Codeg
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner);
         }
 
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getTypeDeclaration(inner);
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpZendExpressivePathHandlerServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpZendExpressivePathHandlerServerCodegen.java
index ee2099b6af8..89827d40246 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpZendExpressivePathHandlerServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PhpZendExpressivePathHandlerServerCodegen.java
@@ -226,7 +226,7 @@ public class PhpZendExpressivePathHandlerServerCodegen extends AbstractPhpCodege
         if (parameter instanceof QueryParameter) {
             QueryParameter queryParameter = (QueryParameter) parameter;
             // array
-            if (ModelUtils.isArraySchema(queryParameter.getSchema())) {
+            if (modelUtils.isArraySchema(queryParameter.getSchema())) {
                 Schema inner = ((ArraySchema) queryParameter.getSchema()).getItems();
                 ArraySchema arraySchema = new ArraySchema();
                 arraySchema.setMinItems(queryParameter.getSchema().getMinItems());
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PowerShellClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PowerShellClientCodegen.java
index 379147ccb2a..707d81c7a84 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PowerShellClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PowerShellClientCodegen.java
@@ -906,11 +906,11 @@ public class PowerShellClientCodegen extends DefaultCodegen implements CodegenCo
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getTypeDeclaration(inner) + "[]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             return "System.Collections.Hashtable";
         } else if (!languageSpecificPrimitives.contains(getSchemaType(p))) {
             return super.getTypeDeclaration(p);
@@ -1272,21 +1272,21 @@ public class PowerShellClientCodegen extends DefaultCodegen implements CodegenCo
     @Override
     public String toDefaultValue(Schema p) {
         if (p.getDefault() != null) {
-            if (ModelUtils.isBooleanSchema(p)) {
+            if (modelUtils.isBooleanSchema(p)) {
                 if (Boolean.valueOf(p.getDefault().toString())) {
                     return "$true";
                 } else {
                     return "$false";
                 }
-            } else if (ModelUtils.isDateSchema(p)) {
+            } else if (modelUtils.isDateSchema(p)) {
                 LOGGER.warn("Default value for `date` not yet supported. Please open an issue with https://github.com/openapitools/openapi-generator");
-            } else if (ModelUtils.isDateTimeSchema(p)) {
+            } else if (modelUtils.isDateTimeSchema(p)) {
                 LOGGER.warn("Default value for `datetime` not yet supported. Please open an issue with https://github.com/openapitools/openapi-generator");
-            } else if (ModelUtils.isNumberSchema(p)) {
+            } else if (modelUtils.isNumberSchema(p)) {
                 return p.getDefault().toString();
-            } else if (ModelUtils.isIntegerSchema(p)) {
+            } else if (modelUtils.isIntegerSchema(p)) {
                 return p.getDefault().toString();
-            } else if (ModelUtils.isStringSchema(p)) {
+            } else if (modelUtils.isStringSchema(p)) {
                 return "\"" + p.getDefault() + "\"";
             }
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ProtobufSchemaCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ProtobufSchemaCodegen.java
index fa9c7015d11..3cce103b6b7 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ProtobufSchemaCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ProtobufSchemaCodegen.java
@@ -300,33 +300,33 @@ public class ProtobufSchemaCodegen extends DefaultCodegen implements CodegenConf
      */
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 if (Boolean.valueOf(p.getDefault().toString()) == false)
                     return "false";
                 else
                     return "true";
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 if (Pattern.compile("\r\n|\r|\n").matcher((String) p.getDefault()).find())
                     return "'''" + p.getDefault() + "'''";
                 else
                     return "'" + p.getDefault() + "'";
             }
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
@@ -484,11 +484,11 @@ public class ProtobufSchemaCodegen extends DefaultCodegen implements CodegenConf
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[str, " + getTypeDeclaration(inner) + "]";
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
index 7ea25de9cb1..66180d0426b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonClientCodegen.java
@@ -142,7 +142,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         }
 
         // default this to true so the python ModelSimple models will be generated
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         LOGGER.info(CodegenConstants.GENERATE_ALIAS_AS_MODEL + " is hard coded to true in this generator. Alias models will only be generated if they contain validations or enums");
 
         Boolean attrNoneIfUnset = false;
@@ -170,7 +170,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
 
     @Override
     public Schema unaliasSchema(Schema schema, Map<String, String> usedImportMappings) {
-        Map<String, Schema> allSchemas = ModelUtils.getSchemas(openAPI);
+        Map<String, Schema> allSchemas = modelUtils.getSchemas();
         if (allSchemas == null || allSchemas.isEmpty()) {
             // skip the warning as the spec can have no model defined
             //LOGGER.warn("allSchemas cannot be null/empty in unaliasSchema. Returned 'schema'");
@@ -178,7 +178,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         }
 
         if (schema != null && StringUtils.isNotEmpty(schema.get$ref())) {
-            String simpleRef = ModelUtils.getSimpleRef(schema.get$ref());
+            String simpleRef = modelUtils.getSimpleRef(schema.get$ref());
             if (usedImportMappings.containsKey(simpleRef)) {
                 LOGGER.debug("Schema unaliasing of {} omitted because aliased class is to be mapped to {}", simpleRef, usedImportMappings.get(simpleRef));
                 return schema;
@@ -190,41 +190,41 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
             } else if (ref.getEnum() != null && !ref.getEnum().isEmpty()) {
                 // top-level enum class
                 return schema;
-            } else if (ModelUtils.isArraySchema(ref)) {
-                if (ModelUtils.isGenerateAliasAsModel(ref)) {
+            } else if (modelUtils.isArraySchema(ref)) {
+                if (modelUtils.isGenerateAliasAsModel(ref)) {
                     return schema; // generate a model extending array
                 } else {
-                    return unaliasSchema(allSchemas.get(ModelUtils.getSimpleRef(schema.get$ref())),
+                    return unaliasSchema(allSchemas.get(modelUtils.getSimpleRef(schema.get$ref())),
                             usedImportMappings);
                 }
-            } else if (ModelUtils.isComposedSchema(ref)) {
+            } else if (modelUtils.isComposedSchema(ref)) {
                 return schema;
-            } else if (ModelUtils.isMapSchema(ref)) {
+            } else if (modelUtils.isMapSchema(ref)) {
                 if (ref.getProperties() != null && !ref.getProperties().isEmpty()) // has at least one property
                     return schema; // treat it as model
                 else {
-                    if (ModelUtils.isGenerateAliasAsModel(ref)) {
+                    if (modelUtils.isGenerateAliasAsModel(ref)) {
                         return schema; // generate a model extending map
                     } else {
                         // treat it as a typical map
-                        return unaliasSchema(allSchemas.get(ModelUtils.getSimpleRef(schema.get$ref())),
+                        return unaliasSchema(allSchemas.get(modelUtils.getSimpleRef(schema.get$ref())),
                                 usedImportMappings);
                     }
                 }
-            } else if (ModelUtils.isObjectSchema(ref)) { // model
+            } else if (modelUtils.isObjectSchema(ref)) { // model
                 if (ref.getProperties() != null && !ref.getProperties().isEmpty()) { // has at least one property
                     return schema;
                 } else {
                     // free form object (type: object)
-                    if (ModelUtils.hasValidation(ref)) {
+                    if (modelUtils.hasValidation(ref)) {
                         return schema;
                     } else if (getAllOfDescendants(simpleRef, openAPI).size() > 0) {
                         return schema;
                     }
-                    return unaliasSchema(allSchemas.get(ModelUtils.getSimpleRef(schema.get$ref())),
+                    return unaliasSchema(allSchemas.get(modelUtils.getSimpleRef(schema.get$ref())),
                             usedImportMappings);
                 }
-            } else if (ModelUtils.hasValidation(ref)) {
+            } else if (modelUtils.hasValidation(ref)) {
                 // non object non array non map schemas that have validations
                 // are returned so we can generate those schemas as models
                 // we do this to:
@@ -232,7 +232,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                 // - use those validations when we use this schema in composed oneOf schemas
                 return schema;
             } else {
-                return unaliasSchema(allSchemas.get(ModelUtils.getSimpleRef(schema.get$ref())), usedImportMappings);
+                return unaliasSchema(allSchemas.get(modelUtils.getSimpleRef(schema.get$ref())), usedImportMappings);
             }
         }
         return schema;
@@ -297,13 +297,13 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         }
 
         String defaultValue = defaultObject.toString();
-        if (ModelUtils.isDateSchema(p)) {
+        if (modelUtils.isDateSchema(p)) {
             defaultValue = pythonDate(defaultObject);
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             defaultValue = pythonDateTime(defaultObject);
-        } else if (ModelUtils.isStringSchema(p) && !ModelUtils.isByteArraySchema(p) && !ModelUtils.isBinarySchema(p) && !ModelUtils.isFileSchema(p) && !ModelUtils.isUUIDSchema(p) && !ModelUtils.isEmailSchema(p)) {
+        } else if (modelUtils.isStringSchema(p) && !modelUtils.isByteArraySchema(p) && !modelUtils.isBinarySchema(p) && !modelUtils.isFileSchema(p) && !modelUtils.isUUIDSchema(p) && !modelUtils.isEmailSchema(p)) {
             defaultValue =  ensureQuotes(defaultValue);
-        } else if (ModelUtils.isBooleanSchema(p)) {
+        } else if (modelUtils.isBooleanSchema(p)) {
             if (Boolean.valueOf(defaultValue) == false) {
                 defaultValue = "False";
             } else {
@@ -359,7 +359,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
          super.postProcessAllModels(objs);
 
         List<String> modelsToRemove = new ArrayList<>();
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         for (String schemaName: allDefinitions.keySet()) {
             Schema refSchema = new Schema().$ref("#/components/schemas/"+schemaName);
             Schema unaliasedSchema = unaliasSchema(refSchema, importMapping);
@@ -467,7 +467,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
     @Override
     public CodegenParameter fromRequestBody(RequestBody body, Set<String> imports, String bodyParameterName) {
         CodegenParameter cp = super.fromRequestBody(body, imports, bodyParameterName);
-        Schema schema = ModelUtils.getSchemaFromRequestBody(body);
+        Schema schema = modelUtils.getSchemaFromRequestBody(body);
         if (schema.get$ref() == null) {
             return cp;
         }
@@ -586,7 +586,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
             oneOfanyOfSchemas.addAll(anyOf);
         }
         for (Schema sc: oneOfanyOfSchemas) {
-            Schema refSchema = ModelUtils.getReferencedSchema(this.openAPI, sc);
+            Schema refSchema = modelUtils.getReferencedSchema(sc);
             addProperties(otherProperties, otherRequired, refSchema);
         }
         Set<String> otherRequiredSet = new HashSet<String>(otherRequired);
@@ -651,7 +651,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                 postProcessModelProperty(cm, cp);
             }
         }
-        Boolean isNotPythonModelSimpleModel = (ModelUtils.isComposedSchema(sc) || ModelUtils.isObjectSchema(sc) || ModelUtils.isMapSchema(sc));
+        Boolean isNotPythonModelSimpleModel = (modelUtils.isComposedSchema(sc) || modelUtils.isObjectSchema(sc) || modelUtils.isMapSchema(sc));
         if (isNotPythonModelSimpleModel) {
             return cm;
         }
@@ -703,7 +703,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         if (sc.get$ref() != null) {
             Schema unaliasedSchema = unaliasSchema(sc, importMapping);
             if (unaliasedSchema.get$ref() != null) {
-                return toModelName(ModelUtils.getSimpleRef(sc.get$ref()));
+                return toModelName(modelUtils.getSimpleRef(sc.get$ref()));
             }
         }
         return null;
@@ -740,27 +740,27 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
             // a composed schema, convert the name to a Python class.
             Schema unaliasedSchema = unaliasSchema(p, importMapping);
             if (unaliasedSchema.get$ref() != null) {
-                String modelName = toModelName(ModelUtils.getSimpleRef(p.get$ref()));
+                String modelName = toModelName(modelUtils.getSimpleRef(p.get$ref()));
                 if (referencedModelNames != null) {
                     referencedModelNames.add(modelName);
                 }
                 return prefix + modelName + fullSuffix;
             }
         }
-        if (ModelUtils.isAnyTypeSchema(openAPI, p)) {
+        if (modelUtils.isAnyTypeSchema(p)) {
             return prefix + "bool, date, datetime, dict, float, int, list, str, none_type" + suffix;
         }
-        // Resolve $ref because ModelUtils.isXYZ methods do not automatically resolve references.
-        if (ModelUtils.isNullable(ModelUtils.getReferencedSchema(this.openAPI, p))) {
+        // Resolve $ref because modelUtils.isXYZ methods do not automatically resolve references.
+        if (modelUtils.isNullable(modelUtils.getReferencedSchema(p))) {
             fullSuffix = ", none_type" + suffix;
         }
-        if (ModelUtils.isFreeFormObject(openAPI, p) && getAdditionalProperties(p) == null) {
+        if (modelUtils.isFreeFormObject(p) && getAdditionalProperties(p) == null) {
             return prefix + "bool, date, datetime, dict, float, int, list, str" + fullSuffix;
         }
-        if ((ModelUtils.isMapSchema(p) || "object".equals(p.getType())) && getAdditionalProperties(p) != null) {
+        if ((modelUtils.isMapSchema(p) || "object".equals(p.getType())) && getAdditionalProperties(p) != null) {
             Schema inner = getAdditionalProperties(p);
             return prefix + "{str: " + getTypeString(inner, "(", ")", referencedModelNames) + "}" + fullSuffix;
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             if (inner == null) {
@@ -777,7 +777,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                 return prefix + getTypeString(inner, "[", "]", referencedModelNames) + fullSuffix;
             }
         }
-        if (ModelUtils.isFileSchema(p)) {
+        if (modelUtils.isFileSchema(p)) {
             return prefix + "file_type" + fullSuffix;
         }
         String baseType = getSchemaType(p);
@@ -801,7 +801,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
 
     @Override
     public String toInstantiationType(Schema property) {
-        if (ModelUtils.isArraySchema(property) || ModelUtils.isMapSchema(property) || property.getAdditionalProperties() != null) {
+        if (modelUtils.isArraySchema(property) || modelUtils.isMapSchema(property) || property.getAdditionalProperties() != null) {
             return getSchemaType(property);
         }
         return super.toInstantiationType(property);
@@ -837,10 +837,10 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         Schema schema = sc;
         String ref = sc.get$ref();
         if (ref != null) {
-            schema = ModelUtils.getSchema(this.openAPI, ModelUtils.getSimpleRef(ref));
+            schema = modelUtils.getSchema(modelUtils.getSimpleRef(ref));
         }
         // TODO handle examples in object models in the future
-        Boolean objectModel = (ModelUtils.isObjectSchema(schema) || ModelUtils.isMapSchema(schema) || ModelUtils.isComposedSchema(schema));
+        Boolean objectModel = (modelUtils.isObjectSchema(schema) || modelUtils.isMapSchema(schema) || modelUtils.isComposedSchema(schema));
         if (objectModel) {
             return null;
         }
@@ -883,9 +883,9 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         Schema sc = schema;
         String ref = schema.get$ref();
         if (ref != null) {
-            sc = ModelUtils.getSchema(this.openAPI, ModelUtils.getSimpleRef(ref));
+            sc = modelUtils.getSchema(modelUtils.getSimpleRef(ref));
         }
-        if (ModelUtils.isStringSchema(sc) && !ModelUtils.isDateSchema(sc) && !ModelUtils.isDateTimeSchema(sc) && !"Number".equalsIgnoreCase(sc.getFormat()) && !ModelUtils.isByteArraySchema(sc) && !ModelUtils.isBinarySchema(sc) && schema.getPattern() == null) {
+        if (modelUtils.isStringSchema(sc) && !modelUtils.isDateSchema(sc) && !modelUtils.isDateTimeSchema(sc) && !"Number".equalsIgnoreCase(sc.getFormat()) && !modelUtils.isByteArraySchema(sc) && !modelUtils.isBinarySchema(sc) && schema.getPattern() == null) {
             return true;
         }
         return false;
@@ -895,7 +895,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         for ( MappedModel mm : disc.getMappedModels() ) {
             String modelName = mm.getModelName();
             Schema modelSchema = getModelNameToSchemaCache().get(modelName);
-            if (ModelUtils.isObjectSchema(modelSchema)) {
+            if (modelUtils.isObjectSchema(modelSchema)) {
                 return mm;
             }
         }
@@ -949,8 +949,8 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
             example = objExample.toString();
         }
         if (null != schema.get$ref()) {
-            Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
-            String ref = ModelUtils.getSimpleRef(schema.get$ref());
+            Map<String, Schema> allDefinitions = modelUtils.getSchemas();
+            String ref = modelUtils.getSimpleRef(schema.get$ref());
             Schema refSchema = allDefinitions.get(ref);
             if (null == refSchema) {
                 LOGGER.warn("Unable to find referenced schema "+schema.get$ref()+"\n");
@@ -958,11 +958,11 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
             }
             String refModelName = getModelName(schema);
             return toExampleValueRecursive(refModelName, refSchema, objExample, indentationLevel, prefix, exampleLine);
-        } else if (ModelUtils.isNullType(schema) || ModelUtils.isAnyTypeSchema(openAPI, schema)) {
+        } else if (modelUtils.isNullType(schema) || modelUtils.isAnyTypeSchema(schema)) {
             // The 'null' type is allowed in OAS 3.1 and above. It is not supported by OAS 3.0.x,
             // though this tooling supports it.
             return fullPrefix + "None" + closeChars;
-        } else if (ModelUtils.isBooleanSchema(schema)) {
+        } else if (modelUtils.isBooleanSchema(schema)) {
             if (objExample == null) {
                 example = "True";
             } else {
@@ -973,32 +973,32 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                 }
             }
             return fullPrefix + example + closeChars;
-        } else if (ModelUtils.isDateSchema(schema)) {
+        } else if (modelUtils.isDateSchema(schema)) {
             if (objExample == null) {
                 example = pythonDate("1970-01-01");
             } else {
                 example = pythonDate(objExample);
             }
             return fullPrefix + example + closeChars;
-        } else if (ModelUtils.isDateTimeSchema(schema)) {
+        } else if (modelUtils.isDateTimeSchema(schema)) {
             if (objExample == null) {
                 example = pythonDateTime("1970-01-01T00:00:00.00Z");
             } else {
                 example = pythonDateTime(objExample);
             }
             return fullPrefix + example + closeChars;
-        } else if (ModelUtils.isBinarySchema(schema)) {
+        } else if (modelUtils.isBinarySchema(schema)) {
             if (objExample == null) {
                 example = "/path/to/file";
             }
             example = "open('" + example + "', 'rb')";
             return fullPrefix + example + closeChars;
-        } else if (ModelUtils.isByteArraySchema(schema)) {
+        } else if (modelUtils.isByteArraySchema(schema)) {
             if (objExample == null) {
                 example = "'YQ=='";
             }
             return fullPrefix + example + closeChars;
-        } else if (ModelUtils.isStringSchema(schema)) {
+        } else if (modelUtils.isStringSchema(schema)) {
             if (objExample == null) {
                 // a BigDecimal:
                 if ("Number".equalsIgnoreCase(schema.getFormat())) {
@@ -1022,14 +1022,14 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                     example = "";
                     int len = schema.getMinLength().intValue();
                     for (int i=0;i<len;i++) example += "a";
-                } else if (ModelUtils.isUUIDSchema(schema)) {
+                } else if (modelUtils.isUUIDSchema(schema)) {
                     example = "046b6c7f-0b8a-43b9-b35d-6489e6daee91";
                 } else {
                     example = "string_example";
                 }
             }
             return  fullPrefix + ensureQuotes(example) + closeChars;
-        } else if (ModelUtils.isIntegerSchema(schema)) {
+        } else if (modelUtils.isIntegerSchema(schema)) {
             if (objExample == null) {
                 if (schema.getMinimum() != null) {
                     example = schema.getMinimum().toString();
@@ -1038,7 +1038,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                 }
             }
             return fullPrefix + example + closeChars;
-        } else if (ModelUtils.isNumberSchema(schema)) {
+        } else if (modelUtils.isNumberSchema(schema)) {
             if (objExample == null) {
                 if (schema.getMinimum() != null) {
                     example = schema.getMinimum().toString();
@@ -1047,7 +1047,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                 }
             }
             return fullPrefix + example + closeChars;
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             if (objExample instanceof Iterable) {
                 // If the example is already a list, return it directly instead of wrongly wrap it in another list
                 return fullPrefix + objExample.toString();
@@ -1057,7 +1057,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
             String itemModelName = getModelName(itemSchema);
             example = fullPrefix + "[" + "\n" + toExampleValueRecursive(itemModelName, itemSchema, objExample, indentationLevel+1, "", exampleLine+1) + ",\n" + closingIndentation + "]" + closeChars;
             return example;
-        } else if (ModelUtils.isMapSchema(schema)) {
+        } else if (modelUtils.isMapSchema(schema)) {
             if (modelName == null) {
                 fullPrefix += "{";
                 closeChars = "}";
@@ -1082,7 +1082,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                 example = fullPrefix + closeChars;
             }
             return example;
-        } else if (ModelUtils.isObjectSchema(schema)) {
+        } else if (modelUtils.isObjectSchema(schema)) {
             if (modelName == null) {
                 fullPrefix += "{";
                 closeChars = "}";
@@ -1101,7 +1101,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
                 }
             }
             return exampleForObjectModel(schema, fullPrefix, closeChars, null, indentationLevel, exampleLine, closingIndentation);
-        } else if (ModelUtils.isComposedSchema(schema)) {
+        } else if (modelUtils.isComposedSchema(schema)) {
             // TODO add examples for composed schema models without discriminators
 
             CodegenDiscriminator disc = createDiscriminator(modelName, schema, openAPI);
@@ -1161,14 +1161,14 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         Schema schema = sc;
         String ref = sc.get$ref();
         if (ref != null) {
-            schema = ModelUtils.getSchema(this.openAPI, ModelUtils.getSimpleRef(ref));
+            schema = modelUtils.getSchema(modelUtils.getSimpleRef(ref));
         }
         Object example = getObjectExample(schema);
         if (example != null) {
             return example;
         } else if (simpleStringSchema(schema)) {
             return propName + "_example";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             ArraySchema arraySchema = (ArraySchema) schema;
             Schema itemSchema = arraySchema.getItems();
             example = getObjectExample(itemSchema);
@@ -1228,7 +1228,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         Content content = requestBody.getContent();
 
         if (content.size() > 1) {
-            // @see ModelUtils.getSchemaFromContent()
+            // @see modelUtils.getSchemaFromContent()
             once(LOGGER).warn("Multiple MediaTypes found, using only the first one");
         }
 
@@ -1283,7 +1283,7 @@ public class PythonClientCodegen extends PythonLegacyClientCodegen {
         if (modelNameToSchemaCache == null) {
             // Create a cache to efficiently lookup schema based on model name.
             Map<String, Schema> m = new HashMap<String, Schema>();
-            ModelUtils.getSchemas(openAPI).forEach((key, schema) -> {
+            modelUtils.getSchemas().forEach((key, schema) -> {
                 m.put(toModelName(key), schema);
             });
             modelNameToSchemaCache = Collections.unmodifiableMap(m);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonLegacyClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonLegacyClientCodegen.java
index 372e6becdbc..7212027caf7 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonLegacyClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/PythonLegacyClientCodegen.java
@@ -469,11 +469,11 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
 
             return getSchemaType(p) + "(str, " + getTypeDeclaration(inner) + ")";
@@ -673,33 +673,33 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
      */
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 if (Boolean.valueOf(p.getDefault().toString()) == false)
                     return "False";
                 else
                     return "True";
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 if (Pattern.compile("\r\n|\r|\n").matcher((String) p.getDefault()).find())
                     return "'''" + p.getDefault() + "'''";
                 else
                     return "'" + ((String) p.getDefault()).replaceAll("'", "\'") + "'";
             }
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
@@ -726,24 +726,24 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
             example = schema.getExample().toString();
         }
 
-        if (ModelUtils.isNullType(schema) && null != example) {
+        if (modelUtils.isNullType(schema) && null != example) {
             // The 'null' type is allowed in OAS 3.1 and above. It is not supported by OAS 3.0.x,
             // though this tooling supports it.
             return "None";
         }
         // correct "true"s into "True"s, since super.toExampleValue uses "toString()" on Java booleans
-        if (ModelUtils.isBooleanSchema(schema) && null!=example) {
+        if (modelUtils.isBooleanSchema(schema) && null!=example) {
             if ("false".equalsIgnoreCase(example)) example = "False";
             else example = "True";
         }
 
         // correct "&#39;"s into "'"s after toString()
-        if (ModelUtils.isStringSchema(schema) && schema.getDefault() != null && !ModelUtils.isDateSchema(schema) && !ModelUtils.isDateTimeSchema(schema)) {
+        if (modelUtils.isStringSchema(schema) && schema.getDefault() != null && !modelUtils.isDateSchema(schema) && !modelUtils.isDateTimeSchema(schema)) {
             example = (String) schema.getDefault();
         }
 
         if (StringUtils.isNotBlank(example) && !"null".equals(example)) {
-            if (ModelUtils.isStringSchema(schema)) {
+            if (modelUtils.isStringSchema(schema)) {
                 example = "'" + example + "'";
             }
             return example;
@@ -752,7 +752,7 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
         if (schema.getEnum() != null && !schema.getEnum().isEmpty()) {
         // Enum case:
             example = schema.getEnum().get(0).toString();
-            if (ModelUtils.isStringSchema(schema)) {
+            if (modelUtils.isStringSchema(schema)) {
                 example = "'" + escapeText(example) + "'";
             }
             if (null == example)
@@ -761,8 +761,8 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
             return example;
         } else if (null != schema.get$ref()) {
         // $ref case:
-            Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
-            String ref = ModelUtils.getSimpleRef(schema.get$ref());
+            Map<String, Schema> allDefinitions = modelUtils.getSchemas();
+            String ref = modelUtils.getSimpleRef(schema.get$ref());
             if (allDefinitions != null) {
                 Schema refSchema = allDefinitions.get(ref);
                 if (null == refSchema) {
@@ -781,18 +781,18 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
                 LOGGER.warn("allDefinitions not defined in toExampleValue!\n");
             }
         }
-        if (ModelUtils.isDateSchema(schema)) {
+        if (modelUtils.isDateSchema(schema)) {
             example = "datetime.datetime.strptime('1975-12-30', '%Y-%m-%d').date()";
             return example;
-        } else if (ModelUtils.isDateTimeSchema(schema)) {
+        } else if (modelUtils.isDateTimeSchema(schema)) {
             example = "datetime.datetime.strptime('2013-10-20 19:20:30.00', '%Y-%m-%d %H:%M:%S.%f')";
             return example;
-        } else if (ModelUtils.isBinarySchema(schema)) {
+        } else if (modelUtils.isBinarySchema(schema)) {
             example = "bytes(b'blah')";
             return example;
-        } else if (ModelUtils.isByteArraySchema(schema)) {
+        } else if (modelUtils.isByteArraySchema(schema)) {
             example = "YQ==";
-        } else if (ModelUtils.isStringSchema(schema)) {
+        } else if (modelUtils.isStringSchema(schema)) {
             // a BigDecimal:
             if ("Number".equalsIgnoreCase(schema.getFormat())) {return "1";}
             if (StringUtils.isNotBlank(schema.getPattern())) {
@@ -822,25 +822,25 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
                     for (int i=0;i<len;i++) example += i;
                 }
             }
-        } else if (ModelUtils.isIntegerSchema(schema)) {
+        } else if (modelUtils.isIntegerSchema(schema)) {
             if (schema.getMinimum() != null)
                 example = schema.getMinimum().toString();
             else
                 example = "56";
-        } else if (ModelUtils.isNumberSchema(schema)) {
+        } else if (modelUtils.isNumberSchema(schema)) {
             if (schema.getMinimum() != null)
                 example = schema.getMinimum().toString();
             else
                 example = "1.337";
-        } else if (ModelUtils.isBooleanSchema(schema)) {
+        } else if (modelUtils.isBooleanSchema(schema)) {
             example = "True";
-        } else if (ModelUtils.isArraySchema(schema)) {
+        } else if (modelUtils.isArraySchema(schema)) {
             if (StringUtils.isNotBlank(schema.getTitle()) && !"null".equals(schema.getTitle())) {
                 included_schemas.add(schema.getTitle());
             }
             ArraySchema arrayschema = (ArraySchema) schema;
             example = "[\n" + indentation_string + toExampleValueRecursive(arrayschema.getItems(), included_schemas, indentation+1) + "\n" + indentation_string + "]";
-        } else if (ModelUtils.isMapSchema(schema)) {
+        } else if (modelUtils.isMapSchema(schema)) {
             if (StringUtils.isNotBlank(schema.getTitle()) && !"null".equals(schema.getTitle())) {
                 included_schemas.add(schema.getTitle());
             }
@@ -850,7 +850,7 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
                 String the_key = "'key'";
                 if (additional.getEnum() != null && !additional.getEnum().isEmpty()) {
                     the_key = additional.getEnum().get(0).toString();
-                    if (ModelUtils.isStringSchema(additional)) {
+                    if (modelUtils.isStringSchema(additional)) {
                         the_key = "'" + escapeText(the_key) + "'";
                     }
                 }
@@ -858,7 +858,7 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
             } else {
                 example = "{ }";
             }
-        } else if (ModelUtils.isObjectSchema(schema)) {
+        } else if (modelUtils.isObjectSchema(schema)) {
             if (StringUtils.isBlank(schema.getTitle())) {
                 example = "None";
                 return example;
@@ -916,7 +916,7 @@ public class PythonLegacyClientCodegen extends DefaultCodegen implements Codegen
             LOGGER.warn("Type " + schema.getType() + " not handled properly in toExampleValue");
         }
 
-        if (ModelUtils.isStringSchema(schema)) {
+        if (modelUtils.isStringSchema(schema)) {
             example = "'" + escapeText(example) + "'";
         }
 
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
index bc9ee0f8432..c9d7c7b23ac 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RClientCodegen.java
@@ -355,11 +355,11 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner)+ "]"; 
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "(" + getTypeDeclaration(inner) + ")";
         }
@@ -629,33 +629,33 @@ public class RClientCodegen extends DefaultCodegen implements CodegenConfig {
      */
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 if (Boolean.valueOf(p.getDefault().toString()) == false)
                     return "FALSE";
                 else
                     return "TRUE";
             }
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             // TODO
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             // TODO
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 if (Pattern.compile("\r\n|\r|\n").matcher((String) p.getDefault()).find())
                     return "'''" + p.getDefault() + "'''";
                 else
                     return "'" + ((String) p.getDefault()).replaceAll("'","\'") + "'";
             }
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java
index 09222896124..12e2c2a3680 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustClientCodegen.java
@@ -440,7 +440,7 @@ public class RustClientCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             if (inner == null) {
@@ -448,7 +448,7 @@ public class RustClientCodegen extends DefaultCodegen implements CodegenConfig {
                 inner = new StringSchema().description("TODO default missing array inner type to string");
             }
             return "Vec<" + getTypeDeclaration(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             if (inner == null) {
                 LOGGER.warn(p.getName() + "(map property) does not have a proper inner type defined. Default to string");
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustServerCodegen.java
index 81b33ca2e94..4a31746ae3b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/RustServerCodegen.java
@@ -266,7 +266,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
                     " (--enable-post-process-file for CLI).");
         }
 
-        if (!Boolean.TRUE.equals(ModelUtils.isGenerateAliasAsModel())) {
+        if (!Boolean.TRUE.equals(modelUtils.isGenerateAliasAsModel())) {
             LOGGER.warn("generateAliasAsModel is set to false, which means array/map will be generated as model instead and the resulting code may have issues. Please enable `generateAliasAsModel` to address the issue.");
         }
 
@@ -606,7 +606,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public CodegenOperation fromOperation(String path, String httpMethod, Operation operation, List<Server> servers) {
-        Map<String, Schema> definitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> definitions = modelUtils.getSchemas();
         CodegenOperation op = super.fromOperation(path, httpMethod, operation, servers);
 
         String pathFormatString = op.path;
@@ -762,7 +762,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
         // Determine the types that this operation produces. `getProducesInfo`
         // simply lists all the types, and then we add the correct imports to
         // the generated library.
-        List<String> produces = new ArrayList<String>(getProducesInfo(openAPI, operation));
+        List<String> produces = new ArrayList<String>(getProducesInfo(operation));
         boolean producesXml = false;
         boolean producesPlainText = false;
         if (produces != null && !produces.isEmpty()) {
@@ -925,7 +925,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
                 Schema response = (Schema) rsp.schema;
                 // Check whether we're returning an object with a defined XML namespace.
                 if (response != null && (!StringUtils.isEmpty(response.get$ref()))) {
-                    Schema model = definitions.get(ModelUtils.getSimpleRef(response.get$ref()));
+                    Schema model = definitions.get(modelUtils.getSimpleRef(response.get$ref()));
                     if ((model != null)) {
                         XML xml = model.getXml();
                         if ((xml != null) && (xml.getNamespace() != null)) {
@@ -1114,7 +1114,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
     // restore things to sensible values.
     @Override
     public CodegenParameter fromRequestBody(RequestBody body, Set<String> imports, String bodyParameterName) {
-        Schema original_schema = ModelUtils.getSchemaFromRequestBody(body);
+        Schema original_schema = modelUtils.getSchemaFromRequestBody(body);
         CodegenParameter codegenParameter = super.fromRequestBody(body, imports, bodyParameterName);
 
         if (StringUtils.isNotBlank(original_schema.get$ref())) {
@@ -1124,7 +1124,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
             codegenParameter.isPrimitiveType = false;
             codegenParameter.isArray = false;
             codegenParameter.isString = false;
-            codegenParameter.isByteArray = ModelUtils.isByteArraySchema(original_schema);
+            codegenParameter.isByteArray = modelUtils.isByteArraySchema(original_schema);
 
 
             // This is a model, so should only have an example if explicitly
@@ -1142,12 +1142,12 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             String innerType = getTypeDeclaration(inner);
             return typeMapping.get("array") + "<" + innerType + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             String innerType = getTypeDeclaration(inner);
             StringBuilder typeDeclaration = new StringBuilder(typeMapping.get("map")).append("<").append(typeMapping.get("string")).append(", ");
@@ -1177,11 +1177,11 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return instantiationTypes.get("array") + "<" + getSchemaType(inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return instantiationTypes.get("map") + "<" + typeMapping.get("string") + ", " + getSchemaType(inner) + ">";
         } else {
@@ -1191,14 +1191,14 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public CodegenModel fromModel(String name, Schema model) {
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel mdl = super.fromModel(name, model);
         mdl.vendorExtensions.put("x-upper-case-name", name.toUpperCase(Locale.ROOT));
         if (!StringUtils.isEmpty(model.get$ref())) {
-            Schema schema = allDefinitions.get(ModelUtils.getSimpleRef(model.get$ref()));
+            Schema schema = allDefinitions.get(modelUtils.getSimpleRef(model.get$ref()));
             mdl.dataType = typeMapping.get(schema.getType());
         }
-        if (ModelUtils.isArraySchema(model)) {
+        if (modelUtils.isArraySchema(model)) {
             ArraySchema am = (ArraySchema) model;
             String xmlName = null;
 
@@ -1213,7 +1213,7 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
                     am.getItems() != null &&
                     !StringUtils.isEmpty(am.getItems().get$ref())) {
                 Schema inner_schema = allDefinitions.get(
-                        ModelUtils.getSimpleRef(am.getItems().get$ref()));
+                        modelUtils.getSimpleRef(am.getItems().get$ref()));
 
                 if (inner_schema.getXml() != null &&
                         inner_schema.getXml().getName() != null) {
@@ -1376,29 +1376,29 @@ public class RustServerCodegen extends DefaultCodegen implements CodegenConfig {
     @Override
     public String toDefaultValue(Schema p) {
         String defaultValue = null;
-        if ((ModelUtils.isNullable(p)) && (p.getDefault() != null) && (p.getDefault().toString().equalsIgnoreCase("null")))
+        if ((modelUtils.isNullable(p)) && (p.getDefault() != null) && (p.getDefault().toString().equalsIgnoreCase("null")))
             return "swagger::Nullable::Null";
-        else if (ModelUtils.isBooleanSchema(p)) {
+        else if (modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 if (p.getDefault().toString().equalsIgnoreCase("false"))
                     defaultValue = "false";
                 else
                     defaultValue = "true";
             }
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             if (p.getDefault() != null) {
                 defaultValue = p.getDefault().toString();
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 defaultValue = p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 defaultValue = "\"" + (String) p.getDefault() + "\".to_string()";
             }
         }
-        if ((defaultValue != null) && (ModelUtils.isNullable(p)))
+        if ((defaultValue != null) && (modelUtils.isNullable(p)))
             defaultValue = "swagger::Nullable::Present(" + defaultValue + ")";
         return defaultValue;
     }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaAkkaClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaAkkaClientCodegen.java
index 138e9bf9c1d..3446cc65b1b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaAkkaClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaAkkaClientCodegen.java
@@ -271,27 +271,27 @@ public class ScalaAkkaClientCodegen extends AbstractScalaCodegen implements Code
             return "None";
         }
 
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return null;
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return null;
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return null;
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             return null;
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             return null;
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
             return "Map[String, " + inner + "].empty ";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
-            if (ModelUtils.isSet(ap)) {
+            if (modelUtils.isSet(ap)) {
                 return "Set[" + inner + "].empty ";
             }
             return "Seq[" + inner + "].empty ";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             return null;
         } else {
             return null;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaFinchServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaFinchServerCodegen.java
index b899a00390b..e581e3f852e 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaFinchServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaFinchServerCodegen.java
@@ -260,11 +260,11 @@ public class ScalaFinchServerCodegen extends DefaultCodegen implements CodegenCo
     @SuppressWarnings("Duplicates")
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
 
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaGatlingCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaGatlingCodegen.java
index 30d8c83d130..ac4cb783768 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaGatlingCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaGatlingCodegen.java
@@ -382,11 +382,11 @@ public class ScalaGatlingCodegen extends AbstractScalaCodegen implements Codegen
      */
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaPlayFrameworkServerCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaPlayFrameworkServerCodegen.java
index cb5f63bf55a..80d8c5b1501 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaPlayFrameworkServerCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaPlayFrameworkServerCodegen.java
@@ -333,48 +333,48 @@ public class ScalaPlayFrameworkServerCodegen extends AbstractScalaCodegen implem
             return p.getDefault().toString();
         }
 
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return "false";
         }
 
-        if (ModelUtils.isDateSchema(p)) {
+        if (modelUtils.isDateSchema(p)) {
             return "LocalDate.now";
         }
 
-        if (ModelUtils.isDateTimeSchema(p)) {
+        if (modelUtils.isDateTimeSchema(p)) {
             return "OffsetDateTime.now";
         }
 
-        if (ModelUtils.isDoubleSchema(p)) {
+        if (modelUtils.isDoubleSchema(p)) {
             return "0.0";
         }
 
-        if (ModelUtils.isFloatSchema(p)) {
+        if (modelUtils.isFloatSchema(p)) {
             return "0.0F";
         }
 
-        if (ModelUtils.isIntegerSchema(p)) {
+        if (modelUtils.isIntegerSchema(p)) {
             return "0";
         }
 
-        if (ModelUtils.isLongSchema(p)) {
+        if (modelUtils.isLongSchema(p)) {
             return "0L";
         }
 
-        if (ModelUtils.isStringSchema(p)) {
+        if (modelUtils.isStringSchema(p)) {
             return "\"\"";
         }
 
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             Schema ap = getAdditionalProperties(p);
             String inner = getSchemaType(ap);
             return "Map.empty[String, " + inner + "]";
         }
 
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             Schema items = ((ArraySchema) p).getItems();
             String inner = getSchemaType(items);
-            if (ModelUtils.isSet(p)) {
+            if (modelUtils.isSet(p)) {
                 return "Set.empty[" + inner + "]";
             }
             return "List.empty[" + inner + "]";
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaSttpClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaSttpClientCodegen.java
index 4e26928038e..5cb31cb5fd0 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaSttpClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaSttpClientCodegen.java
@@ -275,27 +275,27 @@ public class ScalaSttpClientCodegen extends AbstractScalaCodegen implements Code
             return "None";
         }
 
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return null;
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return null;
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return null;
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             return null;
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             return null;
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
             return "Map[String, " + inner + "].empty ";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
-            if (ModelUtils.isSet(ap)) {
+            if (modelUtils.isSet(ap)) {
                 return "Set[" + inner + "].empty ";
             }
             return "Seq[" + inner + "].empty ";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             return null;
         } else {
             return null;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalazClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalazClientCodegen.java
index 8ba9e1f8c45..3b2bf7cd226 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalazClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalazClientCodegen.java
@@ -172,29 +172,29 @@ public class ScalazClientCodegen extends AbstractScalaCodegen implements Codegen
         }
 
         // comment out the following as the default value is no handled differently
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return null;
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return null;
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return null;
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             return null;
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             return null;
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             String inner = getSchemaType(getAdditionalProperties(p));
 
             return "Map.empty[String, " + inner + "] ";
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
-            String collectionType = ModelUtils.isSet(ap) ? typeMapping.get("set") : typeMapping.get("array");
+            String collectionType = modelUtils.isSet(ap) ? typeMapping.get("set") : typeMapping.get("array");
 
             // We assume that users would map these collections to a monoid with an identity function
             // There's no reason to assume mutable structure here (which may make consumption more difficult)
             return collectionType + ".empty[" + inner + "] ";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             return null;
         } else {
             return null;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtml2Generator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtml2Generator.java
index 055b29417da..295145bce09 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtml2Generator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtml2Generator.java
@@ -130,11 +130,11 @@ public class StaticHtml2Generator extends DefaultCodegen implements CodegenConfi
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtmlGenerator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtmlGenerator.java
index 3804de3160a..28eccde24a0 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtmlGenerator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/StaticHtmlGenerator.java
@@ -112,11 +112,11 @@ public class StaticHtmlGenerator extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return getSchemaType(p) + "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return getSchemaType(p) + "[String, " + getTypeDeclaration(inner) + "]";
         }
@@ -207,7 +207,7 @@ public class StaticHtmlGenerator extends DefaultCodegen implements CodegenConfig
         Info info = openAPI.getInfo();
         info.setDescription(toHtml(info.getDescription()));
         info.setTitle(toHtml(info.getTitle()));
-        Map<String, Schema> models = ModelUtils.getSchemas(openAPI);
+        Map<String, Schema> models = modelUtils.getSchemas();
         for (Schema model : models.values()) {
             model.setDescription(toHtml(model.getDescription()));
             model.setTitle(toHtml(model.getTitle()));
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift4Codegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift4Codegen.java
index 59b214a5490..89dbc34ca3f 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift4Codegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift4Codegen.java
@@ -505,11 +505,11 @@ public class Swift4Codegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
             return "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "[String:" + getTypeDeclaration(inner) + "]";
         }
@@ -601,18 +601,18 @@ public class Swift4Codegen extends DefaultCodegen implements CodegenConfig {
     public String toDefaultValue(Schema p) {
         if (p.getEnum() != null && !p.getEnum().isEmpty()) {
             if (p.getDefault() != null) {
-                if (ModelUtils.isStringSchema(p)) {
+                if (modelUtils.isStringSchema(p)) {
                     return "." + toEnumVarName(escapeText((String) p.getDefault()), p.getType());
                 } else {
                     return "." + toEnumVarName(escapeText(p.getDefault().toString()), p.getType());
                 }
             }
         }
-        if (ModelUtils.isIntegerSchema(p) || ModelUtils.isNumberSchema(p) || ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isIntegerSchema(p) || modelUtils.isNumberSchema(p) || modelUtils.isBooleanSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "\"" + escapeText((String) p.getDefault()) + "\"";
             }
@@ -622,9 +622,9 @@ public class Swift4Codegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             return getSchemaType(getAdditionalProperties(p));
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
             return "[" + inner + "]";
@@ -737,7 +737,7 @@ public class Swift4Codegen extends DefaultCodegen implements CodegenConfig {
 
     @Override
     public CodegenModel fromModel(String name, Schema model) {
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel codegenModel = super.fromModel(name, model);
         if (codegenModel.description != null) {
             codegenModel.imports.add("ApiModel");
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift5ClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift5ClientCodegen.java
index 10f44a3f937..c585f460a13 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift5ClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/Swift5ClientCodegen.java
@@ -516,11 +516,11 @@ public class Swift5ClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             Schema inner = ap.getItems();
-            return ModelUtils.isSet(p) ? "Set<" + getTypeDeclaration(inner) + ">" : "[" + getTypeDeclaration(inner) + "]";
-        } else if (ModelUtils.isMapSchema(p)) {
+            return modelUtils.isSet(p) ? "Set<" + getTypeDeclaration(inner) + ">" : "[" + getTypeDeclaration(inner) + "]";
+        } else if (modelUtils.isMapSchema(p)) {
             Schema inner = getAdditionalProperties(p);
             return "[String:" + getTypeDeclaration(inner) + "]";
         }
@@ -612,7 +612,7 @@ public class Swift5ClientCodegen extends DefaultCodegen implements CodegenConfig
     public String toDefaultValue(Schema p) {
         if (p.getEnum() != null && !p.getEnum().isEmpty()) {
             if (p.getDefault() != null) {
-                if (ModelUtils.isStringSchema(p)) {
+                if (modelUtils.isStringSchema(p)) {
                     return "." + toEnumVarName(escapeText((String) p.getDefault()), p.getType());
                 } else {
                     return "." + toEnumVarName(escapeText(p.getDefault().toString()), p.getType());
@@ -620,15 +620,15 @@ public class Swift5ClientCodegen extends DefaultCodegen implements CodegenConfig
             }
         }
         if (p.getDefault() != null) {
-            if (ModelUtils.isIntegerSchema(p) || ModelUtils.isNumberSchema(p) || ModelUtils.isBooleanSchema(p)) {
+            if (modelUtils.isIntegerSchema(p) || modelUtils.isNumberSchema(p) || modelUtils.isBooleanSchema(p)) {
                 return p.getDefault().toString();
-            } else if (ModelUtils.isDateTimeSchema(p)) {
+            } else if (modelUtils.isDateTimeSchema(p)) {
                 // Datetime time stamps in Swift are expressed as Seconds with Microsecond precision.
                 // In Java, we need to be creative to get the Timestamp in Microseconds as a long.
                 Instant instant = ((OffsetDateTime) p.getDefault()).toInstant();
                 long epochMicro = TimeUnit.SECONDS.toMicros(instant.getEpochSecond()) + ((long) instant.get(ChronoField.MICRO_OF_SECOND));
                 return "Date(timeIntervalSince1970: " + String.valueOf(epochMicro) + ".0 / 1_000_000)";
-            } else if (ModelUtils.isStringSchema(p)) {
+            } else if (modelUtils.isStringSchema(p)) {
                 return "\"" + escapeText((String) p.getDefault()) + "\"";
             }
             // TODO: Handle more cases from `ModelUtils`, such as Date
@@ -638,12 +638,12 @@ public class Swift5ClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public String toInstantiationType(Schema p) {
-        if (ModelUtils.isMapSchema(p)) {
+        if (modelUtils.isMapSchema(p)) {
             return getSchemaType(getAdditionalProperties(p));
-        } else if (ModelUtils.isArraySchema(p)) {
+        } else if (modelUtils.isArraySchema(p)) {
             ArraySchema ap = (ArraySchema) p;
             String inner = getSchemaType(ap.getItems());
-            return ModelUtils.isSet(p) ? "Set<" + inner + ">" : "[" + inner + "]";
+            return modelUtils.isSet(p) ? "Set<" + inner + ">" : "[" + inner + "]";
         }
         return null;
     }
@@ -753,7 +753,7 @@ public class Swift5ClientCodegen extends DefaultCodegen implements CodegenConfig
 
     @Override
     public CodegenModel fromModel(String name, Schema model) {
-        Map<String, Schema> allDefinitions = ModelUtils.getSchemas(this.openAPI);
+        Map<String, Schema> allDefinitions = modelUtils.getSchemas();
         CodegenModel codegenModel = super.fromModel(name, model);
         if (codegenModel.description != null) {
             codegenModel.imports.add("ApiModel");
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java
index 20f6ebe614b..34a1f8853d8 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptAngularClientCodegen.java
@@ -362,7 +362,7 @@ public class TypeScriptAngularClientCodegen extends AbstractTypeScriptClientCode
  
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isFileSchema(p)) {
+        if (modelUtils.isFileSchema(p)) {
             return "Blob";
         } else {
             return super.getTypeDeclaration(p);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptClientCodegen.java
index 9e6d5264c8c..74c0c29b237 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptClientCodegen.java
@@ -424,24 +424,24 @@ public class TypeScriptClientCodegen extends DefaultCodegen implements CodegenCo
     protected String getParameterDataType(Parameter parameter, Schema p) {
         // handle enums of various data types
         Schema inner;
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             ArraySchema mp1 = (ArraySchema) p;
             inner = mp1.getItems();
             return this.getSchemaType(p) + "<" + this.getParameterDataType(parameter, inner) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+        } else if (modelUtils.isMapSchema(p)) {
             inner = (Schema) p.getAdditionalProperties();
             return "{ [key: string]: " + this.getParameterDataType(parameter, inner) + "; }";
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             // Handle string enums
             if (p.getEnum() != null) {
                 return enumValuesToEnumTypeUnion(p.getEnum(), "string");
             }
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             // Handle integer enums
             if (p.getEnum() != null) {
                 return numericEnumValuesToEnumTypeUnion(new ArrayList<Number>(p.getEnum()));
             }
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
             // Handle double enums
             if (p.getEnum() != null) {
                 return numericEnumValuesToEnumTypeUnion(new ArrayList<Number>(p.getEnum()));
@@ -488,23 +488,23 @@ public class TypeScriptClientCodegen extends DefaultCodegen implements CodegenCo
 
     @Override
     public String toDefaultValue(Schema p) {
-        if (ModelUtils.isBooleanSchema(p)) {
+        if (modelUtils.isBooleanSchema(p)) {
             return UNDEFINED_VALUE;
-        } else if (ModelUtils.isDateSchema(p)) {
+        } else if (modelUtils.isDateSchema(p)) {
             return UNDEFINED_VALUE;
-        } else if (ModelUtils.isDateTimeSchema(p)) {
+        } else if (modelUtils.isDateTimeSchema(p)) {
             return UNDEFINED_VALUE;
-        } else if (ModelUtils.isNumberSchema(p)) {
+        } else if (modelUtils.isNumberSchema(p)) {
            if (p.getDefault() != null) {
              return p.getDefault().toString();
            }
            return UNDEFINED_VALUE;
-        } else if (ModelUtils.isIntegerSchema(p)) {
+        } else if (modelUtils.isIntegerSchema(p)) {
             if (p.getDefault() != null) {
                 return p.getDefault().toString();
             }
             return UNDEFINED_VALUE;
-        } else if (ModelUtils.isStringSchema(p)) {
+        } else if (modelUtils.isStringSchema(p)) {
             if (p.getDefault() != null) {
                 return "'" + (String) p.getDefault() + "'";
             }
@@ -837,15 +837,15 @@ public class TypeScriptClientCodegen extends DefaultCodegen implements CodegenCo
     @Override
     public String getTypeDeclaration(Schema p) {
         Schema inner;
-        if (ModelUtils.isArraySchema(p)) {
+        if (modelUtils.isArraySchema(p)) {
             inner = ((ArraySchema) p).getItems();
-            return this.getSchemaType(p) + "<" + this.getTypeDeclaration(ModelUtils.unaliasSchema(this.openAPI, inner)) + ">";
-        } else if (ModelUtils.isMapSchema(p)) {
+            return this.getSchemaType(p) + "<" + this.getTypeDeclaration(modelUtils.unaliasSchema(inner)) + ">";
+        } else if (modelUtils.isMapSchema(p)) {
             inner = (Schema) p.getAdditionalProperties();
-            return "{ [key: string]: " + this.getTypeDeclaration(ModelUtils.unaliasSchema(this.openAPI, inner)) + "; }";
-        } else if (ModelUtils.isFileSchema(p)) {
+            return "{ [key: string]: " + this.getTypeDeclaration(modelUtils.unaliasSchema(inner)) + "; }";
+        } else if (modelUtils.isFileSchema(p)) {
             return "HttpFile";
-        } else if (ModelUtils.isBinarySchema(p)) {
+        } else if (modelUtils.isBinarySchema(p)) {
             return "any";
         } else {
             return super.getTypeDeclaration(p);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
index cf591520be9..ce7292e09fc 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptFetchClientCodegen.java
@@ -166,9 +166,9 @@ public class TypeScriptFetchClientCodegen extends AbstractTypeScriptClientCodege
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isFileSchema(p)) {
+        if (modelUtils.isFileSchema(p)) {
             return "Blob";
-        } else if (ModelUtils.isBinarySchema(p)) {
+        } else if (modelUtils.isBinarySchema(p)) {
             return "Blob";
         }
         return super.getTypeDeclaration(p);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptJqueryClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptJqueryClientCodegen.java
index 6e4e2fad7b1..e6d674ca38b 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptJqueryClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptJqueryClientCodegen.java
@@ -94,7 +94,7 @@ public class TypeScriptJqueryClientCodegen extends AbstractTypeScriptClientCodeg
     @Override
     public String getSchemaType(Schema p) {
         String openAPIType = super.getSchemaType(p);
-        if (ModelUtils.isStringSchema(p)) {
+        if (modelUtils.isStringSchema(p)) {
             if (p.getEnum() != null) {
                 return openAPIType;
             }
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptNodeClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptNodeClientCodegen.java
index 0016d23595d..4c3adb8fff9 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptNodeClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptNodeClientCodegen.java
@@ -87,14 +87,14 @@ public class TypeScriptNodeClientCodegen extends AbstractTypeScriptClientCodegen
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isFileSchema(p)) {
+        if (modelUtils.isFileSchema(p)) {
             // There are two file types:
             // 1) RequestFile: the parameter for the request lib when uploading a file
             // (https://github.com/request/request#multipartform-data-multipart-form-uploads)
             // 2) Buffer: for downloading files.
             // Use RequestFile as a default. The return type is fixed to Buffer in handleMethodResponse.
             return "RequestFile";
-        } else if (ModelUtils.isBinarySchema(p)) {
+        } else if (modelUtils.isBinarySchema(p)) {
             return "Buffer";
         }
         return super.getTypeDeclaration(p);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptReduxQueryClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptReduxQueryClientCodegen.java
index 3a2ce5bd90b..b640cfedba7 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptReduxQueryClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptReduxQueryClientCodegen.java
@@ -107,9 +107,9 @@ public class TypeScriptReduxQueryClientCodegen extends AbstractTypeScriptClientC
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isFileSchema(p)) {
+        if (modelUtils.isFileSchema(p)) {
             return "Blob";
-        } else if (ModelUtils.isBinarySchema(p)) {
+        } else if (modelUtils.isBinarySchema(p)) {
             return "Blob";
         }
         return super.getTypeDeclaration(p);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptRxjsClientCodegen.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptRxjsClientCodegen.java
index 2561e1b76fe..7bfbc527d0d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptRxjsClientCodegen.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/TypeScriptRxjsClientCodegen.java
@@ -108,9 +108,9 @@ public class TypeScriptRxjsClientCodegen extends AbstractTypeScriptClientCodegen
 
     @Override
     public String getTypeDeclaration(Schema p) {
-        if (ModelUtils.isFileSchema(p)) {
+        if (modelUtils.isFileSchema(p)) {
             return "Blob";
-        } else if (ModelUtils.isBinarySchema(p)) {
+        } else if (modelUtils.isBinarySchema(p)) {
             return "Blob";
         }
         return super.getTypeDeclaration(p);
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
index 270f0bc2609..aa2f5866192 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/utils/ModelUtils.java
@@ -252,27 +252,27 @@ public class ModelUtils {
         if (allOperations != null) {
             for (Operation operation : allOperations) {
                 //Params:
-                visitParameters(openAPI, operation.getParameters(), visitor, visitedSchemas);
+                visitParameters(operation.getParameters(), visitor, visitedSchemas);
 
                 //RequestBody:
-                RequestBody requestBody = getReferencedRequestBody(openAPI, operation.getRequestBody());
+                RequestBody requestBody = getReferencedRequestBody(operation.getRequestBody());
                 if (requestBody != null) {
-                    visitContent(openAPI, requestBody.getContent(), visitor, visitedSchemas);
+                    visitContent(requestBody.getContent(), visitor, visitedSchemas);
                 }
 
                 //Responses:
                 if (operation.getResponses() != null) {
                     for (ApiResponse r : operation.getResponses().values()) {
-                        ApiResponse apiResponse = getReferencedApiResponse(openAPI, r);
+                        ApiResponse apiResponse = getReferencedApiResponse(r);
                         if (apiResponse != null) {
-                            visitContent(openAPI, apiResponse.getContent(), visitor, visitedSchemas);
+                            visitContent(apiResponse.getContent(), visitor, visitedSchemas);
                             if (apiResponse.getHeaders() != null) {
                                 for (Entry<String, Header> e : apiResponse.getHeaders().entrySet()) {
                                     Header header = getReferencedHeader(e.getValue());
                                     if (header.getSchema() != null) {
                                         visitSchema(header.getSchema(), e.getKey(), visitedSchemas, visitor);
                                     }
-                                    visitContent(openAPI, header.getContent(), visitor, visitedSchemas);
+                                    visitContent(header.getContent(), visitor, visitedSchemas);
                                 }
                             }
                         }
@@ -282,7 +282,7 @@ public class ModelUtils {
                 //Callbacks:
                 if (operation.getCallbacks() != null) {
                     for (Callback c : operation.getCallbacks().values()) {
-                        Callback callback = getReferencedCallback(openAPI, c);
+                        Callback callback = getReferencedCallback(c);
                         if (callback != null) {
                             for (PathItem p : callback.values()) {
                                 visitPathItem(p, openAPI, visitor, visitedSchemas);
@@ -293,19 +293,19 @@ public class ModelUtils {
             }
         }
         //Params:
-        visitParameters(openAPI, pathItem.getParameters(), visitor, visitedSchemas);
+        visitParameters(pathItem.getParameters(), visitor, visitedSchemas);
     }
 
-    private void visitParameters(OpenAPI openAPI, List<Parameter> parameters, OpenAPISchemaVisitor visitor,
+    private void visitParameters(List<Parameter> parameters, OpenAPISchemaVisitor visitor,
                                         List<String> visitedSchemas) {
         if (parameters != null) {
             for (Parameter p : parameters) {
-                Parameter parameter = getReferencedParameter(openAPI, p);
+                Parameter parameter = getReferencedParameter(p);
                 if (parameter != null) {
                     if (parameter.getSchema() != null) {
                         visitSchema(parameter.getSchema(), null, visitedSchemas, visitor);
                     }
-                    visitContent(openAPI, parameter.getContent(), visitor, visitedSchemas);
+                    visitContent(parameter.getContent(), visitor, visitedSchemas);
                 } else {
                     once(LOGGER).warn("Unreferenced parameter(s) found.");
                 }
@@ -313,7 +313,7 @@ public class ModelUtils {
         }
     }
 
-    private void visitContent(OpenAPI openAPI, Content content, OpenAPISchemaVisitor visitor, List<String> visitedSchemas) {
+    private void visitContent(Content content, OpenAPISchemaVisitor visitor, List<String> visitedSchemas) {
         if (content != null) {
             for (Entry<String, MediaType> e : content.entrySet()) {
                 if (e.getValue().getSchema() != null) {
@@ -834,14 +834,13 @@ public class ModelUtils {
     /**
      * If a Schema contains a reference to another Schema with '$ref', returns the referenced Schema if it is found or the actual Schema in the other cases.
      *
-     * @param openAPI specification being checked
      * @param schema  potentially containing a '$ref'
      * @return schema without '$ref'
      */
-    public Schema getReferencedSchema(OpenAPI openAPI, Schema schema) {
+    public Schema getReferencedSchema(Schema schema) {
         if (schema != null && StringUtils.isNotEmpty(schema.get$ref())) {
             String name = getSimpleRef(schema.get$ref());
-            Schema referencedSchema = getSchema(openAPI, name);
+            Schema referencedSchema = getSchema(name);
             if (referencedSchema != null) {
                 return referencedSchema;
             }
@@ -849,7 +848,7 @@ public class ModelUtils {
         return schema;
     }
 
-    public Schema getSchema(OpenAPI openAPI, String name) {
+    public Schema getSchema(String name) {
         if (name == null) {
             return null;
         }
@@ -894,14 +893,13 @@ public class ModelUtils {
     /**
      * If a RequestBody contains a reference to an other RequestBody with '$ref', returns the referenced RequestBody if it is found or the actual RequestBody in the other cases.
      *
-     * @param openAPI     specification being checked
      * @param requestBody potentially containing a '$ref'
      * @return requestBody without '$ref'
      */
-    public RequestBody getReferencedRequestBody(OpenAPI openAPI, RequestBody requestBody) {
+    public RequestBody getReferencedRequestBody(RequestBody requestBody) {
         if (requestBody != null && StringUtils.isNotEmpty(requestBody.get$ref())) {
             String name = getSimpleRef(requestBody.get$ref());
-            RequestBody referencedRequestBody = getRequestBody(openAPI, name);
+            RequestBody referencedRequestBody = getRequestBody(name);
             if (referencedRequestBody != null) {
                 return referencedRequestBody;
             }
@@ -909,7 +907,7 @@ public class ModelUtils {
         return requestBody;
     }
 
-    public RequestBody getRequestBody(OpenAPI openAPI, String name) {
+    public RequestBody getRequestBody(String name) {
         if (name == null) {
             return null;
         }
@@ -923,14 +921,13 @@ public class ModelUtils {
     /**
      * If a ApiResponse contains a reference to an other ApiResponse with '$ref', returns the referenced ApiResponse if it is found or the actual ApiResponse in the other cases.
      *
-     * @param openAPI     specification being checked
      * @param apiResponse potentially containing a '$ref'
      * @return apiResponse without '$ref'
      */
-    public ApiResponse getReferencedApiResponse(OpenAPI openAPI, ApiResponse apiResponse) {
+    public ApiResponse getReferencedApiResponse(ApiResponse apiResponse) {
         if (apiResponse != null && StringUtils.isNotEmpty(apiResponse.get$ref())) {
             String name = getSimpleRef(apiResponse.get$ref());
-            ApiResponse referencedApiResponse = getApiResponse(openAPI, name);
+            ApiResponse referencedApiResponse = getApiResponse(name);
             if (referencedApiResponse != null) {
                 return referencedApiResponse;
             }
@@ -938,7 +935,7 @@ public class ModelUtils {
         return apiResponse;
     }
 
-    public ApiResponse getApiResponse(OpenAPI openAPI, String name) {
+    public ApiResponse getApiResponse(String name) {
         if (name == null) {
             return null;
         }
@@ -952,14 +949,13 @@ public class ModelUtils {
     /**
      * If a Parameter contains a reference to an other Parameter with '$ref', returns the referenced Parameter if it is found or the actual Parameter in the other cases.
      *
-     * @param openAPI   specification being checked
      * @param parameter potentially containing a '$ref'
      * @return parameter without '$ref'
      */
-    public Parameter getReferencedParameter(OpenAPI openAPI, Parameter parameter) {
+    public Parameter getReferencedParameter(Parameter parameter) {
         if (parameter != null && StringUtils.isNotEmpty(parameter.get$ref())) {
             String name = getSimpleRef(parameter.get$ref());
-            Parameter referencedParameter = getParameter(openAPI, name);
+            Parameter referencedParameter = getParameter(name);
             if (referencedParameter != null) {
                 return referencedParameter;
             }
@@ -967,7 +963,7 @@ public class ModelUtils {
         return parameter;
     }
 
-    public Parameter getParameter(OpenAPI openAPI, String name) {
+    public Parameter getParameter(String name) {
         if (name == null) {
             return null;
         }
@@ -981,14 +977,13 @@ public class ModelUtils {
     /**
      * If a Callback contains a reference to an other Callback with '$ref', returns the referenced Callback if it is found or the actual Callback in the other cases.
      *
-     * @param openAPI  specification being checked
      * @param callback potentially containing a '$ref'
      * @return callback without '$ref'
      */
-    public Callback getReferencedCallback(OpenAPI openAPI, Callback callback) {
+    public Callback getReferencedCallback(Callback callback) {
         if (callback != null && StringUtils.isNotEmpty(callback.get$ref())) {
             String name = getSimpleRef(callback.get$ref());
-            Callback referencedCallback = getCallback(openAPI, name);
+            Callback referencedCallback = getCallback(name);
             if (referencedCallback != null) {
                 return referencedCallback;
             }
@@ -996,7 +991,7 @@ public class ModelUtils {
         return callback;
     }
 
-    public Callback getCallback(OpenAPI openAPI, String name) {
+    public Callback getCallback(String name) {
         if (name == null) {
             return null;
         }
@@ -1567,13 +1562,12 @@ public class ModelUtils {
      * For OAS 2.0 documents, return the value of the 'swagger' attribute.
      * For OAS 3.x documents, return the value of the 'openapi' attribute.
      *
-     * @param openAPI the object that encapsulates the OAS document.
      * @param location the URL of the OAS document.
      * @param auths the list of authorization values to access the remote URL.
      *
      * @return the version of the OpenAPI document.
      */
-    public SemVer getOpenApiVersion(OpenAPI openAPI, String location, List<AuthorizationValue> auths) {
+    public SemVer getOpenApiVersion(String location, List<AuthorizationValue> auths) {
         String version;
         try {
             JsonNode document = readWithInfo(location, auths);
@@ -1616,7 +1610,7 @@ public class ModelUtils {
      * @param schema the OAS schema.
      * @return true if the schema value can be an arbitrary type.
      */
-    public boolean isAnyTypeSchema(OpenAPI openAPI, Schema schema) {
+    public boolean isAnyTypeSchema(Schema schema) {
         if (schema == null) {
             once(LOGGER).error("Schema cannot be null in isAnyTypeSchema check");
             return false;
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiEvaluator.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiEvaluator.java
index 56097b74d0f..5584726488d 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiEvaluator.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiEvaluator.java
@@ -43,14 +43,16 @@ public class OpenApiEvaluator implements Validator<OpenAPI> {
         OpenApiSchemaValidations schemaValidations = new OpenApiSchemaValidations(ruleConfiguration);
         OpenApiOperationValidations operationValidations = new OpenApiOperationValidations(ruleConfiguration);
 
+        ModelUtils modelUtils = new ModelUtils(specification);
+
         if (ruleConfiguration.isEnableUnusedSchemasRecommendation()) {
             ValidationRule unusedSchema = ValidationRule.create(Severity.WARNING, "Unused schema", "A schema was determined to be unused.", s -> ValidationRule.Pass.empty());
-            ModelUtils.getUnusedSchemas(specification).forEach(schemaName -> validationResult.addResult(Validated.invalid(unusedSchema, "Unused model: " + schemaName)));
+            modelUtils.getUnusedSchemas().forEach(schemaName -> validationResult.addResult(Validated.invalid(unusedSchema, "Unused model: " + schemaName)));
         }
 
         // Get list of all schemas under /components/schemas, including nested schemas defined inline and composed schema.
         // The validators must be able to validate every schema defined in the OAS document.
-        List<Schema> schemas = ModelUtils.getAllSchemas(specification);
+        List<Schema> schemas = modelUtils.getAllSchemas(specification);
         schemas.forEach(schema -> {
             SchemaWrapper wrapper = new SchemaWrapper(specification, schema);
             validationResult.consume(schemaValidations.validate(wrapper));
@@ -95,7 +97,7 @@ public class OpenApiEvaluator implements Validator<OpenAPI> {
         }
 
         parameters.forEach(parameter -> {
-            parameter = ModelUtils.getReferencedParameter(specification, parameter);
+            parameter = modelUtils.getReferencedParameter(parameter);
             ParameterWrapper wrapper = new ParameterWrapper(specification, parameter);
             validationResult.consume(parameterValidations.validate(wrapper));
         });
diff --git a/modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiSchemaValidations.java b/modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiSchemaValidations.java
index 43d68ae1af3..c70d8babf9e 100644
--- a/modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiSchemaValidations.java
+++ b/modules/openapi-generator/src/main/java/org/openapitools/codegen/validations/oas/OpenApiSchemaValidations.java
@@ -92,7 +92,7 @@ class OpenApiSchemaValidations extends GenericValidator<SchemaWrapper> {
      * Note: the validator invokes checkNullType() for every top-level schema in the OAS document. The method
      * is not called for nested schemas that are defined inline.
      * 
-     * @param schema An input schema, regardless of the type of schema.
+     * @param schemaWrapper An input schema, regardless of the type of schema.
      * @return {@link ValidationRule.Pass} if the check succeeds, otherwise {@link ValidationRule.Fail}
      */
     private static ValidationRule.Result checkNullType(SchemaWrapper schemaWrapper) {
@@ -102,7 +102,8 @@ class OpenApiSchemaValidations extends GenericValidator<SchemaWrapper> {
             SemVer version = new SemVer(schemaWrapper.getOpenAPI().getOpenapi());
             if (version.atLeast("3.0") && version.compareTo(new SemVer("3.1")) < 0) {
                 // OAS spec is 3.0.x
-                if (ModelUtils.isNullType(schema)) {
+                ModelUtils modelUtils = new ModelUtils(null);
+                if (modelUtils.isNullType(schema)) {
                     result = new ValidationRule.Fail();
                     String name = schema.getName();
                     if (name == null) {
@@ -123,7 +124,7 @@ class OpenApiSchemaValidations extends GenericValidator<SchemaWrapper> {
      * <p>
      * The 'nullable' attribute is supported in OpenAPI Specification 3.0.x, but it is deprecated in OpenAPI 3.1 and above.
      * 
-     * @param schema An input schema, regardless of the type of schema
+     * @param schemaWrapper An input schema, regardless of the type of schema
      * @return {@link ValidationRule.Pass} if the check succeeds, otherwise {@link ValidationRule.Fail}
      */
     private static ValidationRule.Result checkNullableAttribute(SchemaWrapper schemaWrapper) {
@@ -132,7 +133,8 @@ class OpenApiSchemaValidations extends GenericValidator<SchemaWrapper> {
         if (schemaWrapper.getOpenAPI() != null) {
             SemVer version = new SemVer(schemaWrapper.getOpenAPI().getOpenapi());
             if (version.atLeast("3.1")) {
-                if (ModelUtils.isNullable(schema)) {
+                ModelUtils modelUtils = new ModelUtils(null);
+                if (modelUtils.isNullable(schema)) {
                     result = new ValidationRule.Fail();
                     String name = schema.getName();
                     if (name == null) {
@@ -157,7 +159,7 @@ class OpenApiSchemaValidations extends GenericValidator<SchemaWrapper> {
      * <p>
      * The type must be one of the following values: null, boolean, object, array, number, string, integer.
      * 
-     * @param schema An input schema, regardless of the type of schema
+     * @param schemaWrapper An input schema, regardless of the type of schema
      * @return {@link ValidationRule.Pass} if the check succeeds, otherwise {@link ValidationRule.Fail}
      */
     private static ValidationRule.Result checkInvalidType(SchemaWrapper schemaWrapper) {
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
index cef1d10be35..9570ae98e84 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultCodegenTest.java
@@ -76,8 +76,8 @@ public class DefaultCodegenTest {
 
         final DefaultCodegen codegen = new DefaultCodegen();
 
-        Assert.assertEquals(codegen.hasBodyParameter(openAPI, pingOperation), false);
-        Assert.assertEquals(codegen.hasBodyParameter(openAPI, createOperation), true);
+        Assert.assertEquals(codegen.hasBodyParameter(pingOperation), false);
+        Assert.assertEquals(codegen.hasBodyParameter(createOperation), true);
     }
 
     @Test(expectedExceptions = RuntimeException.class)
@@ -110,13 +110,13 @@ public class DefaultCodegenTest {
                 .responses(
                         new ApiResponses().addApiResponse("201", new ApiResponse()
                                 .description("Created response")));
-        Set<String> createConsumesInfo = DefaultCodegen.getConsumesInfo(openAPI, createOperation);
+        final DefaultCodegen codegen = new DefaultCodegen();
+        Set<String> createConsumesInfo = codegen.getConsumesInfo(createOperation);
         Assert.assertEquals(createConsumesInfo.size(), 2);
         Assert.assertTrue(createConsumesInfo.contains("application/json"), "contains 'application/json'");
         Assert.assertTrue(createConsumesInfo.contains("application/xml"), "contains 'application/xml'");
-        Set<String> createProducesInfo = DefaultCodegen.getProducesInfo(openAPI, createOperation);
+        Set<String> createProducesInfo = codegen.getProducesInfo(createOperation);
         Assert.assertEquals(createProducesInfo.size(), 0);
-        final DefaultCodegen codegen = new DefaultCodegen();
         codegen.setOpenAPI(openAPI);
         CodegenOperation coCreate = codegen.fromOperation("somepath", "post", createOperation, null);
         Assert.assertTrue(coCreate.hasConsumes);
@@ -126,10 +126,10 @@ public class DefaultCodegenTest {
         Operation updateOperationWithRef = new Operation()
                 .requestBody(new RequestBody().$ref("#/components/requestBodies/MyRequestBody"))
                 .responses(new ApiResponses().addApiResponse("201", new ApiResponse().$ref("#/components/responses/MyResponse")));
-        Set<String> updateConsumesInfo = DefaultCodegen.getConsumesInfo(openAPI, updateOperationWithRef);
+        Set<String> updateConsumesInfo = codegen.getConsumesInfo(updateOperationWithRef);
         Assert.assertEquals(updateConsumesInfo.size(), 1);
         Assert.assertTrue(updateConsumesInfo.contains("application/json"), "contains 'application/json'");
-        Set<String> updateProducesInfo = DefaultCodegen.getProducesInfo(openAPI, updateOperationWithRef);
+        Set<String> updateProducesInfo = codegen.getProducesInfo(updateOperationWithRef);
         Assert.assertEquals(updateProducesInfo.size(), 1);
         Assert.assertTrue(updateProducesInfo.contains("application/xml"), "contains 'application/xml'");
 
@@ -218,7 +218,7 @@ public class DefaultCodegenTest {
         final DefaultCodegen codegen = new DefaultCodegen();
         codegen.setOpenAPI(openAPI);
 
-        Schema requestBodySchema = ModelUtils.getSchemaFromRequestBody(openAPI.getPaths().get("/fake").getGet().getRequestBody());
+        Schema requestBodySchema = codegen.getModelUtils().getSchemaFromRequestBody(openAPI.getPaths().get("/fake").getGet().getRequestBody());
         CodegenParameter codegenParameter = codegen.fromFormProperty("enum_form_string", (Schema) requestBodySchema.getProperties().get("enum_form_string"), new HashSet<String>());
 
         Assert.assertEquals(codegenParameter.defaultValue, "-efg");
@@ -229,13 +229,14 @@ public class DefaultCodegenTest {
         // Test with OAS 2.0 document.
         String location = "src/test/resources/2_0/python-client-experimental/petstore-with-fake-endpoints-models-for-testing.yaml";
         OpenAPI openAPI = TestUtils.parseFlattenSpec(location);
-        SemVer version = ModelUtils.getOpenApiVersion(openAPI, location, null);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+        SemVer version = modelUtils.getOpenApiVersion(location, null);
         Assert.assertEquals(version, new SemVer("2.0.0"));
 
         // Test with OAS 3.0 document.
         location = "src/test/resources/3_0/python/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml";
         openAPI = TestUtils.parseFlattenSpec(location);
-        version = ModelUtils.getOpenApiVersion(openAPI, location, null);
+        version = modelUtils.getOpenApiVersion(location, null);
         Assert.assertEquals(version, new SemVer("3.0.0"));
     }
 
@@ -245,11 +246,12 @@ public class DefaultCodegenTest {
         DefaultCodegen codegen = new DefaultCodegen();
         codegen.setOpenAPI(openAPI);
         codegen.setDisallowAdditionalPropertiesIfNotPresent(true);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         Schema schema = openAPI.getComponents().getSchemas().get("AdditionalPropertiesClass");
         Assert.assertEquals(schema.getAdditionalProperties(), null);
 
-        Schema addProps = ModelUtils.getAdditionalProperties(openAPI, schema);
+        Schema addProps = modelUtils.getAdditionalProperties(schema);
         // The petstore-with-fake-endpoints-models-for-testing.yaml does not set the
         // 'additionalProperties' keyword for this model, hence assert the value to be null.
         Assert.assertNull(addProps);
@@ -275,7 +277,7 @@ public class DefaultCodegenTest {
         // We cannot differentiate between 'additionalProperties' not present and
         // additionalProperties: true.
         Assert.assertNull(child.getAdditionalProperties());
-        addProps = ModelUtils.getAdditionalProperties(openAPI, child);
+        addProps = modelUtils.getAdditionalProperties(child);
         Assert.assertNull(addProps);
 
         child = m.get("map_without_additional_properties");
@@ -286,7 +288,7 @@ public class DefaultCodegenTest {
         // We cannot differentiate between 'additionalProperties' not present and
         // additionalProperties: false.
         Assert.assertNull(child.getAdditionalProperties());
-        addProps = ModelUtils.getAdditionalProperties(openAPI, child);
+        addProps = modelUtils.getAdditionalProperties(child);
         Assert.assertNull(addProps);
     }
 
@@ -296,13 +298,14 @@ public class DefaultCodegenTest {
         DefaultCodegen codegen = new DefaultCodegen();
         codegen.setDisallowAdditionalPropertiesIfNotPresent(false);
         codegen.setOpenAPI(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         Schema schema = openAPI.getComponents().getSchemas().get("AdditionalPropertiesClass");
         Assert.assertNull(schema.getAdditionalProperties());
 
         // When the 'additionalProperties' keyword is not present, the schema may be
         // extended with any undeclared properties.
-        Schema addProps = ModelUtils.getAdditionalProperties(openAPI, schema);
+        Schema addProps = modelUtils.getAdditionalProperties(schema);
         Assert.assertNotNull(addProps);
         Assert.assertTrue(addProps instanceof ObjectSchema);
         CodegenModel cm = codegen.fromModel("AdditionalPropertiesClass", schema);
@@ -320,7 +323,7 @@ public class DefaultCodegenTest {
         // which means by default undeclared properties are allowed.
         Assert.assertNotNull(child);
         Assert.assertNull(child.getAdditionalProperties());
-        addProps = ModelUtils.getAdditionalProperties(openAPI, child);
+        addProps = modelUtils.getAdditionalProperties(child);
         Assert.assertNotNull(addProps);
         Assert.assertTrue(addProps instanceof ObjectSchema);
 
@@ -329,7 +332,7 @@ public class DefaultCodegenTest {
         // which means by default undeclared properties are allowed.
         Assert.assertNotNull(child);
         Assert.assertNull(child.getAdditionalProperties());
-        addProps = ModelUtils.getAdditionalProperties(openAPI, child);
+        addProps = modelUtils.getAdditionalProperties(child);
         Assert.assertNotNull(addProps);
         Assert.assertTrue(addProps instanceof ObjectSchema);
 
@@ -341,7 +344,7 @@ public class DefaultCodegenTest {
         // additionalProperties: true.
         Assert.assertNotNull(child.getAdditionalProperties());
         Assert.assertEquals(child.getAdditionalProperties(), Boolean.TRUE);
-        addProps = ModelUtils.getAdditionalProperties(openAPI, child);
+        addProps = modelUtils.getAdditionalProperties(child);
         Assert.assertNotNull(addProps);
         Assert.assertTrue(addProps instanceof ObjectSchema);
 
@@ -353,7 +356,7 @@ public class DefaultCodegenTest {
         // additionalProperties: false.
         Assert.assertNotNull(child.getAdditionalProperties());
         Assert.assertEquals(child.getAdditionalProperties(), Boolean.FALSE);
-        addProps = ModelUtils.getAdditionalProperties(openAPI, child);
+        addProps = modelUtils.getAdditionalProperties(child);
         Assert.assertNull(addProps);
     }
 
@@ -371,7 +374,7 @@ public class DefaultCodegenTest {
         // extended with any undeclared properties.
         // However, in legacy 'additionalProperties' mode, this is interpreted as
         // 'no additional properties are allowed'.
-        Schema addProps = ModelUtils.getAdditionalProperties(openAPI, schema);
+        Schema addProps = codegen.getModelUtils().getAdditionalProperties(schema);
         Assert.assertNull(addProps);
     }
 
@@ -430,7 +433,7 @@ public class DefaultCodegenTest {
         final DefaultCodegen codegen = new DefaultCodegen();
 
         Operation operation = openAPI.getPaths().get("/state").getPost();
-        Schema schema = ModelUtils.getSchemaFromRequestBody(operation.getRequestBody());
+        Schema schema = codegen.getModelUtils().getSchemaFromRequestBody(operation.getRequestBody());
         String type = codegen.getSchemaType(schema);
 
         Assert.assertNotNull(type);
@@ -1347,7 +1350,7 @@ public class DefaultCodegenTest {
         // for us to check a model's children we need to run generator.generateModels
         // because children are assigned in config.updateAllModels which is invoked in generator.generateModels
         List<File> files = new ArrayList<>();
-        List<String> filteredSchemas = ModelUtils.getSchemasUsedOnlyInFormParam(openAPI);
+        List<String> filteredSchemas = generator.getModelUtils().getSchemasUsedOnlyInFormParam();
         List<Object> allModels = new ArrayList<>();
         generator.generateModels(files, allModels, filteredSchemas);
 
@@ -2401,7 +2404,7 @@ public class DefaultCodegenTest {
         CodegenProperty mapWithAddPropsSchema;
 
         // make sure isGenerateAliasAsModel is false
-        boolean isGenerateAliasAsModel = ModelUtils.isGenerateAliasAsModel();
+        boolean isGenerateAliasAsModel = codegen.getModelUtils().isGenerateAliasAsModel();
         if (isGenerateAliasAsModel) {
             GlobalSettings.setProperty("generateAliasAsModel", "false");
         }
@@ -2454,7 +2457,7 @@ public class DefaultCodegenTest {
         CodegenParameter mapWithAddPropsSchema;
 
         // make sure isGenerateAliasAsModel is false
-        boolean isGenerateAliasAsModel = ModelUtils.isGenerateAliasAsModel();
+        boolean isGenerateAliasAsModel = codegen.getModelUtils().isGenerateAliasAsModel();
         if (isGenerateAliasAsModel) {
             GlobalSettings.setProperty("generateAliasAsModel", "false");
         }
@@ -2507,7 +2510,7 @@ public class DefaultCodegenTest {
         CodegenResponse mapWithAddPropsSchema;
 
         // make sure isGenerateAliasAsModel is false
-        boolean isGenerateAliasAsModel = ModelUtils.isGenerateAliasAsModel();
+        boolean isGenerateAliasAsModel = codegen.getModelUtils().isGenerateAliasAsModel();
         if (isGenerateAliasAsModel) {
             GlobalSettings.setProperty("generateAliasAsModel", "false");
         }
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultGeneratorTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultGeneratorTest.java
index 8ac2fe4a512..8eb2c284095 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultGeneratorTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/DefaultGeneratorTest.java
@@ -394,6 +394,8 @@ public class DefaultGeneratorTest {
     @Test
     public void testRefModelValidationProperties() {
         OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/2_0/refAliasedPrimitiveWithValidation.yml");
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+
         ClientOptInput opts = new ClientOptInput();
         opts.openAPI(openAPI);
         DefaultCodegen config = new DefaultCodegen();
@@ -412,7 +414,7 @@ public class DefaultGeneratorTest {
         Assert.assertEquals(stringRegex.getPattern(), expectedPattern);
 
         // Validate when we alias/unalias
-        Schema unaliasedStringRegex = ModelUtils.unaliasSchema(openAPI, stringRegex);
+        Schema unaliasedStringRegex = modelUtils.unaliasSchema(stringRegex);
         Assert.assertEquals(unaliasedStringRegex.getPattern(), expectedPattern);
 
         // Validate when converting to property
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/InlineModelResolverTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/InlineModelResolverTest.java
index e612f985de3..a0a9e359c20 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/InlineModelResolverTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/InlineModelResolverTest.java
@@ -351,6 +351,7 @@ public class InlineModelResolverTest {
     public void resolveInlineRequestBody() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         RequestBody requestBodyReference = openAPI
                 .getPaths()
@@ -359,15 +360,15 @@ public class InlineModelResolverTest {
                 .getRequestBody();
         assertNotNull(requestBodyReference.get$ref());
 
-        RequestBody requestBody = ModelUtils.getReferencedRequestBody(openAPI, requestBodyReference);
+        RequestBody requestBody = modelUtils.getReferencedRequestBody(requestBodyReference);
         MediaType mediaType = requestBody.getContent().get("application/json");
-        assertTrue(ModelUtils.getReferencedSchema(openAPI, mediaType.getSchema()) instanceof ObjectSchema);
+        assertTrue(modelUtils.getReferencedSchema(mediaType.getSchema()) instanceof ObjectSchema);
 
-        ObjectSchema schema = (ObjectSchema) ModelUtils.getReferencedSchema(openAPI, mediaType.getSchema());
+        ObjectSchema schema = (ObjectSchema) modelUtils.getReferencedSchema(mediaType.getSchema());
         assertTrue(schema.getProperties().get("name") instanceof StringSchema);
         assertNotNull(schema.getProperties().get("address").get$ref());
 
-        Schema address = ModelUtils.getReferencedSchema(openAPI, schema.getProperties().get("address"));
+        Schema address = modelUtils.getReferencedSchema(schema.getProperties().get("address"));
         assertTrue(address.getProperties().get("street") instanceof StringSchema);
     }
 
@@ -375,11 +376,12 @@ public class InlineModelResolverTest {
     public void resolveInlineRequestBodyWithRequired() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         RequestBody requestBodyReference = openAPI.getPaths().get("/resolve_inline_request_body_with_required").getPost().getRequestBody();
         assertTrue(requestBodyReference.getRequired());
 
-        RequestBody referencedRequestBody = ModelUtils.getReferencedRequestBody(openAPI, requestBodyReference);
+        RequestBody referencedRequestBody = modelUtils.getReferencedRequestBody(requestBodyReference);
         assertTrue(referencedRequestBody.getRequired());
     }
 
@@ -414,6 +416,7 @@ public class InlineModelResolverTest {
     public void resolveInlineArrayRequestBody() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         MediaType mediaType = openAPI
                 .getPaths()
@@ -429,7 +432,7 @@ public class InlineModelResolverTest {
         assertNotNull(requestBody.getItems().get$ref());
         assertEquals("#/components/schemas/InlineObject", requestBody.getItems().get$ref());
 
-        Schema items = ModelUtils.getReferencedSchema(openAPI, ((ArraySchema) mediaType.getSchema()).getItems());
+        Schema items = modelUtils.getReferencedSchema(((ArraySchema) mediaType.getSchema()).getItems());
         assertTrue(items.getProperties().get("street") instanceof StringSchema);
         assertTrue(items.getProperties().get("city") instanceof StringSchema);
     }
@@ -456,6 +459,7 @@ public class InlineModelResolverTest {
     public void resolveInlineArrayResponse() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         MediaType mediaType = openAPI
                 .getPaths()
@@ -471,7 +475,7 @@ public class InlineModelResolverTest {
         ArraySchema responseSchema = (ArraySchema) mediaType.getSchema();
         assertEquals("#/components/schemas/inline_response_200", responseSchema.getItems().get$ref());
 
-        Schema items = ModelUtils.getReferencedSchema(openAPI, responseSchema.getItems());
+        Schema items = modelUtils.getReferencedSchema(responseSchema.getItems());
         assertTrue(items.getProperties().get("array_response_property") instanceof StringSchema);
     }
 
@@ -497,6 +501,7 @@ public class InlineModelResolverTest {
     public void resolveInlineObjectResponseWithAdditionalProperties() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         MediaType mediaType = openAPI
                 .getPaths()
@@ -511,7 +516,7 @@ public class InlineModelResolverTest {
         Object additionalPropertiesObject = mediaType.getSchema().getAdditionalProperties();
         assertTrue(additionalPropertiesObject instanceof Schema);
 
-        Schema additionalProperties = ModelUtils.getReferencedSchema(openAPI, (Schema)additionalPropertiesObject);
+        Schema additionalProperties = modelUtils.getReferencedSchema((Schema)additionalPropertiesObject);
         assertNotNull(additionalProperties);
         assertTrue(additionalProperties.getProperties().get("resolve_inline_object_response_with_additional_properties") instanceof StringSchema);
     }
@@ -547,6 +552,7 @@ public class InlineModelResolverTest {
         );
 
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         MediaType mediaType = openAPI
             .getPaths()
@@ -562,14 +568,14 @@ public class InlineModelResolverTest {
         assertNotNull(additionalProperties.get$ref());
         assertTrue(additionalProperties.get$ref().startsWith("#/components/schemas/inline_response_"));
 
-        Schema referencedSchema = ModelUtils.getReferencedSchema(openAPI, additionalProperties);
+        Schema referencedSchema = modelUtils.getReferencedSchema(additionalProperties);
         Schema referencedSchemaProperty = (Schema) referencedSchema.getProperties().get("resolve_inline_map_schema_in_response_property");
 
         assertEquals(
             "#/components/schemas/_resolve_inline_map_schema_in_response_resolve_inline_map_schema_in_response_property",
             referencedSchemaProperty.get$ref()
         );
-        assertNotNull(ModelUtils.getReferencedSchema(openAPI, referencedSchemaProperty));
+        assertNotNull(modelUtils.getReferencedSchema(referencedSchemaProperty));
     }
 
     @Test
@@ -631,6 +637,7 @@ public class InlineModelResolverTest {
     public void arbitraryRequestBodyArrayProperty() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         MediaType mediaType = openAPI
                 .getPaths()
@@ -645,7 +652,7 @@ public class InlineModelResolverTest {
         ArraySchema requestBodySchema = (ArraySchema) mediaType.getSchema();
         assertNotNull(requestBodySchema.getItems().get$ref());
 
-        Schema referencedSchema = ModelUtils.getReferencedSchema(openAPI, requestBodySchema.getItems());
+        Schema referencedSchema = modelUtils.getReferencedSchema(requestBodySchema.getItems());
         assertTrue(referencedSchema.getProperties().get("arbitrary_request_body_array_property") instanceof ObjectSchema);
     }
 
@@ -690,6 +697,7 @@ public class InlineModelResolverTest {
     public void arbitraryObjectResponseArrayInline() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         MediaType mediaType = openAPI
                 .getPaths()
@@ -704,7 +712,7 @@ public class InlineModelResolverTest {
         ArraySchema schema = (ArraySchema) mediaType.getSchema();
         assertNotNull(schema.getItems().get$ref());
 
-        Schema referencedSchema = ModelUtils.getReferencedSchema(openAPI, schema.getItems());
+        Schema referencedSchema = modelUtils.getReferencedSchema(schema.getItems());
         assertTrue(referencedSchema.getProperties().get("arbitrary_object_response_array_inline") instanceof ObjectSchema);
 
         ObjectSchema arbitaryObject = (ObjectSchema) referencedSchema.getProperties().get("arbitrary_object_response_array_inline");
@@ -763,10 +771,11 @@ public class InlineModelResolverTest {
 
 
     private void checkComposedChildren(OpenAPI openAPI, List<Schema> children, String key) {
+        ModelUtils modelUtils = new ModelUtils(openAPI);
         assertNotNull(children);
         Schema inlined = children.get(0);
         assertEquals("#/components/schemas/ComposedObjectModelInline_" + key, inlined.get$ref());
-        Schema child = ModelUtils.getReferencedSchema(openAPI, inlined);
+        Schema child = modelUtils.getReferencedSchema(inlined);
         assertNotNull(child.getProperties());
         assertNotNull(child.getProperties().get("composed_object_model_inline_" + key));
     }
@@ -790,6 +799,7 @@ public class InlineModelResolverTest {
     public void inheritanceWithInlineDiscriminator() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/2_0/regression_6905.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         assertTrue(openAPI.getComponents().getSchemas().get("PartyType") instanceof StringSchema);
         assertTrue(openAPI.getComponents().getSchemas().get("CustomerType") instanceof StringSchema);
@@ -812,8 +822,8 @@ public class InlineModelResolverTest {
         // Party
         ComposedSchema party = (ComposedSchema) openAPI.getComponents().getSchemas().get("Party");
         List<Schema> partySchemas = party.getAllOf();
-        Schema entity = ModelUtils.getReferencedSchema(openAPI, partySchemas.get(0));
-        Schema partyAllOf = ModelUtils.getReferencedSchema(openAPI, partySchemas.get(1));
+        Schema entity = modelUtils.getReferencedSchema(partySchemas.get(0));
+        Schema partyAllOf = modelUtils.getReferencedSchema(partySchemas.get(1));
 
         assertEquals(partySchemas.get(0).get$ref(), "#/components/schemas/Entity");
         assertEquals(partySchemas.get(1).get$ref(), "#/components/schemas/Party_allOf");
@@ -827,7 +837,7 @@ public class InlineModelResolverTest {
 
         // Contact
         ComposedSchema contact = (ComposedSchema) openAPI.getComponents().getSchemas().get("Contact");
-        Schema contactAllOf = ModelUtils.getReferencedSchema(openAPI, contact.getAllOf().get(1));
+        Schema contactAllOf = modelUtils.getReferencedSchema(contact.getAllOf().get(1));
 
         assertEquals(contact.getExtensions().get("x-discriminator-value"), "contact");
         assertEquals(contact.getAllOf().get(0).get$ref(), "#/components/schemas/Party");
@@ -838,7 +848,7 @@ public class InlineModelResolverTest {
         // Customer
         ComposedSchema customer = (ComposedSchema) openAPI.getComponents().getSchemas().get("Customer");
         List<Schema> customerSchemas = customer.getAllOf();
-        Schema customerAllOf = ModelUtils.getReferencedSchema(openAPI, customerSchemas.get(1));
+        Schema customerAllOf = modelUtils.getReferencedSchema(customerSchemas.get(1));
 
         assertEquals(customerSchemas.get(0).get$ref(), "#/components/schemas/Party");
         assertNull(customer.getDiscriminator());
@@ -858,7 +868,7 @@ public class InlineModelResolverTest {
         // Person
         ComposedSchema person = (ComposedSchema) openAPI.getComponents().getSchemas().get("Person");
         List<Schema> personSchemas = person.getAllOf();
-        Schema personAllOf = ModelUtils.getReferencedSchema(openAPI, personSchemas.get(1));
+        Schema personAllOf = modelUtils.getReferencedSchema(personSchemas.get(1));
 
         // Discriminators are not defined at this level in the schema doc
         assertEquals(personSchemas.get(0).get$ref(), "#/components/schemas/Customer");
@@ -875,7 +885,7 @@ public class InlineModelResolverTest {
         // Organization
         ComposedSchema organization = (ComposedSchema) openAPI.getComponents().getSchemas().get("Organization");
         List<Schema> organizationSchemas = organization.getAllOf();
-        Schema organizationAllOf = ModelUtils.getReferencedSchema(openAPI, organizationSchemas.get(1));
+        Schema organizationAllOf = modelUtils.getReferencedSchema(organizationSchemas.get(1));
 
         // Discriminators are not defined at this level in the schema doc
         assertEquals(organizationSchemas.get(0).get$ref(), "#/components/schemas/Customer");
@@ -911,6 +921,7 @@ public class InlineModelResolverTest {
     public void emptyExampleOnStringTypeModels() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         MediaType mediaType = openAPI
                 .getPaths()
@@ -926,17 +937,18 @@ public class InlineModelResolverTest {
         ArraySchema schema = (ArraySchema) mediaType.getSchema();
         assertEquals("#/components/schemas/EmptyExampleOnStringTypeModels", schema.getItems().get$ref());
 
-        assertTrue(ModelUtils.getReferencedSchema(openAPI, schema.getItems()) instanceof StringSchema);
-        assertNull(ModelUtils.getReferencedSchema(openAPI, schema.getItems()).getExample());
+        assertTrue(modelUtils.getReferencedSchema(schema.getItems()) instanceof StringSchema);
+        assertNull(modelUtils.getReferencedSchema(schema.getItems()).getExample());
     }
 
     @Test
     public void nullable() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         Schema nullablePropertyReference = (Schema) openAPI.getComponents().getSchemas().get("InlinePropertyIsNullable").getProperties().get("nullable_property");
-        Schema nullablePropertySchema = ModelUtils.getReferencedSchema(openAPI, nullablePropertyReference);
+        Schema nullablePropertySchema = modelUtils.getReferencedSchema(nullablePropertyReference);
         assertTrue(nullablePropertySchema.getNullable());
 
 
@@ -950,7 +962,7 @@ public class InlineModelResolverTest {
                 .getSchema()
                 .getProperties()
                 .get("nullable_request_body_property");
-        Schema nullableRequestBodySchema = ModelUtils.getReferencedSchema(openAPI, nullableRequestBodyReference);
+        Schema nullableRequestBodySchema = modelUtils.getReferencedSchema(nullableRequestBodyReference);
         assertTrue(nullableRequestBodySchema.getNullable());
     }
 
@@ -958,6 +970,7 @@ public class InlineModelResolverTest {
     public void callbacks() {
         OpenAPI openAPI = TestUtils.parseSpec("src/test/resources/3_0/inline_model_resolver.yaml");
         new InlineModelResolver().flatten(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         RequestBody callbackRequestBodyReference = openAPI
                 .getPaths()
@@ -973,7 +986,7 @@ public class InlineModelResolverTest {
         RequestBody resolvedCallbackRequestBody = openAPI
                 .getComponents()
                 .getRequestBodies()
-                .get(ModelUtils.getSimpleRef(callbackRequestBodyReference.get$ref()));
+                .get(modelUtils.getSimpleRef(callbackRequestBodyReference.get$ref()));
 
         Schema callbackRequestSchemaReference = resolvedCallbackRequestBody
                 .getContent()
@@ -984,7 +997,7 @@ public class InlineModelResolverTest {
         Schema resolvedCallbackSchema = openAPI
                 .getComponents()
                 .getSchemas()
-                .get(ModelUtils.getSimpleRef(callbackRequestSchemaReference.get$ref()));
+                .get(modelUtils.getSimpleRef(callbackRequestSchemaReference.get$ref()));
 
         Map properties = resolvedCallbackSchema.getProperties();
         assertTrue(properties.get("notificationId") instanceof StringSchema);
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/TestUtils.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/TestUtils.java
index d510d5fef02..237978dc247 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/TestUtils.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/TestUtils.java
@@ -59,17 +59,19 @@ public class TestUtils {
      */
     public static OpenAPI parseSpec(String specFilePath) {
         OpenAPI openAPI = new OpenAPIParser().readLocation(specFilePath, null, new ParseOptions()).getOpenAPI();
+        ModelUtils modelUtils = new ModelUtils(openAPI);
         // Invoke helper function to get the original swagger version.
         // See https://github.com/swagger-api/swagger-parser/pull/1374
         // Also see https://github.com/swagger-api/swagger-parser/issues/1369.
-        ModelUtils.getOpenApiVersion(openAPI, specFilePath, null);
+        modelUtils.getOpenApiVersion(specFilePath, null);
         return openAPI;
     }
 
     public static OpenAPI parseContent(String jsonOrYaml) {
         OpenAPI openAPI = new OpenAPIParser().readContents(jsonOrYaml, null, null).getOpenAPI();
+        ModelUtils modelUtils = new ModelUtils(openAPI);
         // Invoke helper function to get the original swagger version.
-        ModelUtils.getOpenApiVersion(openAPI, jsonOrYaml, null);
+        modelUtils.getOpenApiVersion(jsonOrYaml, null);
         return openAPI;
     }
 
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/go/AbstractGoCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/go/AbstractGoCodegenTest.java
index b1e0d924fa8..d9f46b0774f 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/go/AbstractGoCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/go/AbstractGoCodegenTest.java
@@ -72,23 +72,23 @@ public class AbstractGoCodegenTest {
 
         // Create an array schema with item type set to the array alias
         Schema<?> schema = new ArraySchema().items(new Schema().$ref("#/components/schemas/NestedArray"));
-
-        ModelUtils.setGenerateAliasAsModel(false);
+        ModelUtils modelUtils = new ModelUtils(codegen.getOpenAPI());
+        modelUtils.setGenerateAliasAsModel(false);
         String defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "[][]int32");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "[]NestedArray");
 
         // Create a map schema with additionalProperties type set to array alias
         schema = new MapSchema().additionalProperties(new Schema().$ref("#/components/schemas/NestedArray"));
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "map[string][]int32");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "map[string]NestedArray");
     }
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/AbstractJavaCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/AbstractJavaCodegenTest.java
index 4f8b9807378..2d8e8cfdf6a 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/AbstractJavaCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/java/AbstractJavaCodegenTest.java
@@ -418,26 +418,27 @@ public class AbstractJavaCodegenTest {
         // Create an alias to an array schema
         Schema<?> nestedArraySchema = new ArraySchema().items(new IntegerSchema().format("int32"));
         codegen.setOpenAPI(new OpenAPI().components(new Components().addSchemas("NestedArray", nestedArraySchema)));
+        ModelUtils modelUtils = new ModelUtils(codegen.getOpenAPI());
 
         // Create an array schema with item type set to the array alias
         schema = new ArraySchema().items(new Schema().$ref("#/components/schemas/NestedArray"));
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         defaultValue = codegen.toDefaultValue(schema);
         Assert.assertEquals(defaultValue, "new ArrayList<List<Integer>>()");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         defaultValue = codegen.toDefaultValue(schema);
         Assert.assertEquals(defaultValue, "new ArrayList<NestedArray>()");
 
         // Create a map schema with additionalProperties type set to array alias
         schema = new MapSchema().additionalProperties(new Schema().$ref("#/components/schemas/NestedArray"));
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         defaultValue = codegen.toDefaultValue(schema);
         Assert.assertEquals(defaultValue, "new HashMap<String, List<Integer>>()");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         defaultValue = codegen.toDefaultValue(schema);
         Assert.assertEquals(defaultValue, "new HashMap<String, NestedArray>()");
         
@@ -483,15 +484,16 @@ public class AbstractJavaCodegenTest {
         // Create an alias to an array schema
         Schema<?> nestedArraySchema = new ArraySchema().items(new IntegerSchema().format("int32"));
         codegen.setOpenAPI(new OpenAPI().components(new Components().addSchemas("NestedArray", nestedArraySchema)));
+        ModelUtils modelUtils = new ModelUtils(codegen.getOpenAPI());
 
         // Create an array schema with item type set to the array alias
         schema = new ArraySchema().items(new Schema().$ref("#/components/schemas/NestedArray"));
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "List<List<Integer>>");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "List<NestedArray>");
 
@@ -499,22 +501,22 @@ public class AbstractJavaCodegenTest {
         schema = new ArraySchema().items(new Schema().$ref("#/components/schemas/NestedArray"));
         schema.setUniqueItems(true);
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "Set<List<Integer>>");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "Set<NestedArray>");
 
         // Create a map schema with additionalProperties type set to array alias
         schema = new MapSchema().additionalProperties(new Schema().$ref("#/components/schemas/NestedArray"));
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "Map<String, List<Integer>>");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         defaultValue = codegen.getTypeDeclaration(schema);
         Assert.assertEquals(defaultValue, "Map<String, NestedArray>");
     }
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonClientTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonClientTest.java
index 683d4aa4b02..d06687d29b3 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonClientTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/python/PythonClientTest.java
@@ -330,7 +330,7 @@ public class PythonClientTest {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/python/petstore-with-fake-endpoints-models-for-testing-with-http-signature.yaml");
         final DefaultCodegen codegen = new PythonClientCodegen();
 
-        Schema modelSchema = ModelUtils.getSchema(openAPI, "DateTimeTest");
+        Schema modelSchema = codegen.getModelUtils().getSchema("DateTimeTest");
         String defaultValue = codegen.toDefaultValue(modelSchema);
         Assert.assertEquals(defaultValue, "dateutil_parser('2010-01-01T10:10:10.000111+01:00')");
     }
@@ -421,7 +421,7 @@ public class PythonClientTest {
         codegen.setOpenAPI(openAPI);
 
         String modelName = "FreeFormWithValidation";
-        Schema modelSchema = ModelUtils.getSchema(openAPI, modelName);
+        Schema modelSchema = codegen.getModelUtils().getSchema(modelName);
         final CodegenModel model = codegen.fromModel(modelName, modelSchema);
         Assert.assertEquals((int) model.getMinProperties(), 1);
     }
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/TypeScriptClientCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/TypeScriptClientCodegenTest.java
index 350af16ebb8..ca925ec98e4 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/TypeScriptClientCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/TypeScriptClientCodegenTest.java
@@ -25,19 +25,21 @@ public class TypeScriptClientCodegenTest {
             new Schema().$ref("#/components/schemas/Child")
         );
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        ModelUtils modelUtils = new ModelUtils(api);
+
+        modelUtils.setGenerateAliasAsModel(false);
         Assert.assertEquals(codegen.getTypeDeclaration(parentSchema), "Array<Array<string>>");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         Assert.assertEquals(codegen.getTypeDeclaration(parentSchema), "Array<Child>");
 
         // Same for Map
         parentSchema = new MapSchema().additionalProperties(new Schema().$ref("#/components/schemas/Child"));
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         Assert.assertEquals(codegen.getTypeDeclaration(parentSchema), "{ [key: string]: Array<string>; }");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         Assert.assertEquals(codegen.getTypeDeclaration(parentSchema), "{ [key: string]: Child; }");
     }
 
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java
index f6b0678a414..c9aa302746f 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchClientCodegenTest.java
@@ -76,6 +76,7 @@ public class TypeScriptFetchClientCodegenTest {
         Schema<?> childSchema = new ArraySchema().items(new StringSchema());
 
         OpenAPI api = TestUtils.createOpenAPI();
+        ModelUtils modelUtils = new ModelUtils(api);
         api.getComponents().addSchemas("Child", childSchema);
 
         TypeScriptFetchClientCodegen codegen = new TypeScriptFetchClientCodegen();
@@ -86,19 +87,19 @@ public class TypeScriptFetchClientCodegenTest {
             new Schema().$ref("#/components/schemas/Child")
         );
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         Assert.assertEquals(codegen.getTypeDeclaration(parentSchema), "Array<Array<string>>");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         Assert.assertEquals(codegen.getTypeDeclaration(parentSchema), "Array<Child>");
 
         // Same for Map
         parentSchema = new MapSchema().additionalProperties(new Schema().$ref("#/components/schemas/Child"));
 
-        ModelUtils.setGenerateAliasAsModel(false);
+        modelUtils.setGenerateAliasAsModel(false);
         Assert.assertEquals(codegen.getTypeDeclaration(parentSchema), "{ [key: string]: Array<string>; }");
 
-        ModelUtils.setGenerateAliasAsModel(true);
+        modelUtils.setGenerateAliasAsModel(true);
         Assert.assertEquals(codegen.getTypeDeclaration(parentSchema), "{ [key: string]: Child; }");
     }
 
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchModelTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchModelTest.java
index 8b43b94a8ce..7082abab2ef 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchModelTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/typescript/fetch/TypeScriptFetchModelTest.java
@@ -42,7 +42,7 @@ import java.util.Locale;
 /*
 import static io.swagger.codegen.CodegenConstants.IS_ENUM_EXT_NAME;
 import static io.swagger.codegen.languages.helpers.ExtensionHelper.getBooleanValue;
-import static io.swagger.codegen.utils.ModelUtils.updateCodegenPropertyEnum;
+import static io.swagger.codegen.utils.modelUtils.updateCodegenPropertyEnum;
 */
 
 @SuppressWarnings("static-method")
diff --git a/modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/ModelUtilsTest.java b/modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/ModelUtilsTest.java
index a8ed4e34bbe..425d5343722 100644
--- a/modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/ModelUtilsTest.java
+++ b/modules/openapi-generator/src/test/java/org/openapitools/codegen/utils/ModelUtilsTest.java
@@ -33,7 +33,8 @@ public class ModelUtilsTest {
     @Test
     public void testGetAllUsedSchemas() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/unusedSchemas.yaml");
-        List<String> allUsedSchemas = ModelUtils.getAllUsedSchemas(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+        List<String> allUsedSchemas = modelUtils.getAllUsedSchemas();
         List<String> expectedallUsedSchemas = Arrays.asList(
                 "SomeObj1",
                 "SomeObj2",
@@ -85,7 +86,8 @@ public class ModelUtilsTest {
     @Test
     public void testGetUnusedSchemas() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/unusedSchemas.yaml");
-        List<String> unusedSchemas = ModelUtils.getUnusedSchemas(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+        List<String> unusedSchemas = modelUtils.getUnusedSchemas();
         List<String> expectedUnusedSchemas = Arrays.asList(
                 "UnusedObj1",
                 "UnusedObj2",
@@ -104,7 +106,8 @@ public class ModelUtilsTest {
     @Test
     public void testSchemasUsedOnlyInFormParam() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/unusedSchemas.yaml");
-        List<String> unusedSchemas = ModelUtils.getSchemasUsedOnlyInFormParam(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+        List<String> unusedSchemas = modelUtils.getSchemasUsedOnlyInFormParam();
         Assert.assertEquals(unusedSchemas.size(), 3);
         //SomeObj2 is only used in an 'application/x-www-form-urlencoded' request
         Assert.assertTrue(unusedSchemas.contains("SomeObj2"), "contains 'SomeObj2'");
@@ -117,24 +120,27 @@ public class ModelUtilsTest {
     @Test
     public void testNoComponentsSection() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/3_0/ping.yaml");
-        List<String> unusedSchemas = ModelUtils.getSchemasUsedOnlyInFormParam(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+        List<String> unusedSchemas = modelUtils.getSchemasUsedOnlyInFormParam();
         Assert.assertEquals(unusedSchemas.size(), 0);
     }
 
     @Test
     public void testGlobalProducesConsumes() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/2_0/globalProducesConsumesTest.yaml");
-        List<String> unusedSchemas = ModelUtils.getSchemasUsedOnlyInFormParam(openAPI);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+        List<String> unusedSchemas = modelUtils.getSchemasUsedOnlyInFormParam();
         Assert.assertEquals(unusedSchemas.size(), 0);
     }
 
     @Test
     public void testIsModelAllowsEmptyBaseModel() {
         final OpenAPI openAPI = TestUtils.parseFlattenSpec("src/test/resources/2_0/emptyBaseModel.yaml");
-        Schema commandSchema = ModelUtils.getSchema(openAPI, "Command");
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+        Schema commandSchema = modelUtils.getSchema("Command");
 
-        Assert.assertTrue(ModelUtils.isModel(commandSchema));
-        Assert.assertFalse(ModelUtils.isFreeFormObject(openAPI, commandSchema));
+        Assert.assertTrue(modelUtils.isModel(commandSchema));
+        Assert.assertFalse(modelUtils.isFreeFormObject(commandSchema));
     }
 
     @Test
@@ -143,12 +149,13 @@ public class ModelUtilsTest {
 
         OpenAPI openAPI = TestUtils.createOpenAPI();
         openAPI.getComponents().addSchemas("OtherObj", otherObj);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         Schema notExistingReferencedSchema = new Schema().$ref("NotExisting");
-        Schema result1 = ModelUtils.getReferencedSchema(openAPI, notExistingReferencedSchema);
+        Schema result1 = modelUtils.getReferencedSchema(notExistingReferencedSchema);
         Assert.assertEquals(result1, notExistingReferencedSchema);
 
-        Schema result2 = ModelUtils.getReferencedSchema(openAPI, new Schema().$ref("#/components/schemas/OtherObj"));
+        Schema result2 = modelUtils.getReferencedSchema(new Schema().$ref("#/components/schemas/OtherObj"));
         Assert.assertEquals(result2, otherObj);
     }
 
@@ -158,12 +165,13 @@ public class ModelUtilsTest {
 
         OpenAPI openAPI = TestUtils.createOpenAPI();
         openAPI.getComponents().addRequestBodies("OtherRequestBody", otherRequestBody);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         RequestBody notExistingRequestBody = new RequestBody().$ref("NotExisting");
-        RequestBody result1 = ModelUtils.getReferencedRequestBody(openAPI, notExistingRequestBody);
+        RequestBody result1 = modelUtils.getReferencedRequestBody(notExistingRequestBody);
         Assert.assertEquals(result1, notExistingRequestBody);
 
-        RequestBody result2 = ModelUtils.getReferencedRequestBody(openAPI, new RequestBody().$ref("#/components/requestBodies/OtherRequestBody"));
+        RequestBody result2 = modelUtils.getReferencedRequestBody(new RequestBody().$ref("#/components/requestBodies/OtherRequestBody"));
         Assert.assertEquals(result2, otherRequestBody);
     }
 
@@ -173,12 +181,13 @@ public class ModelUtilsTest {
 
         OpenAPI openAPI = TestUtils.createOpenAPI();
         openAPI.getComponents().addResponses("OtherApiResponse", otherApiResponse);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         ApiResponse notExistingApiResponse = new ApiResponse().$ref("NotExisting");
-        ApiResponse result1 = ModelUtils.getReferencedApiResponse(openAPI, notExistingApiResponse);
+        ApiResponse result1 = modelUtils.getReferencedApiResponse(notExistingApiResponse);
         Assert.assertEquals(result1, notExistingApiResponse);
 
-        ApiResponse result2 = ModelUtils.getReferencedApiResponse(openAPI, new ApiResponse().$ref("#/components/responses/OtherApiResponse"));
+        ApiResponse result2 = modelUtils.getReferencedApiResponse(new ApiResponse().$ref("#/components/responses/OtherApiResponse"));
         Assert.assertEquals(result2, otherApiResponse);
     }
 
@@ -188,12 +197,13 @@ public class ModelUtilsTest {
 
         OpenAPI openAPI = TestUtils.createOpenAPI();
         openAPI.getComponents().addParameters("OtherParameter", otherParameter);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
         Parameter notExistingParameter = new Parameter().$ref("NotExisting");
-        Parameter result1 = ModelUtils.getReferencedParameter(openAPI, notExistingParameter);
+        Parameter result1 = modelUtils.getReferencedParameter(notExistingParameter);
         Assert.assertEquals(result1, notExistingParameter);
 
-        Parameter result2 = ModelUtils.getReferencedParameter(openAPI, new Parameter().$ref("#/components/parameters/OtherParameter"));
+        Parameter result2 = modelUtils.getReferencedParameter(new Parameter().$ref("#/components/parameters/OtherParameter"));
         Assert.assertEquals(result2, otherParameter);
     }
 
@@ -211,8 +221,9 @@ public class ModelUtilsTest {
         Schema refToComposedSchema = new Schema().$ref("#/components/schemas/SomeComposedSchema");
 
         OpenAPI openAPI = TestUtils.createOpenAPIWithOneSchema("SomeComposedSchema", composedSchema);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
-        Assert.assertEquals(refToComposedSchema, ModelUtils.unaliasSchema(openAPI, refToComposedSchema, new HashMap<>()));
+        Assert.assertEquals(refToComposedSchema, modelUtils.unaliasSchema(refToComposedSchema, new HashMap<>()));
     }
 
     @Test
@@ -223,38 +234,41 @@ public class ModelUtilsTest {
         importMappings.put("Email","foo.bar.Email");
 
         OpenAPI openAPI = TestUtils.createOpenAPIWithOneSchema("Email", stringSchema);
+        ModelUtils modelUtils = new ModelUtils(openAPI);
 
-        Assert.assertEquals(emailSchema, ModelUtils.unaliasSchema(openAPI, emailSchema, importMappings));
-        Assert.assertEquals(stringSchema, ModelUtils.unaliasSchema(openAPI, emailSchema, new HashMap<>()));
+        Assert.assertEquals(emailSchema, modelUtils.unaliasSchema(emailSchema, importMappings));
+        Assert.assertEquals(stringSchema, modelUtils.unaliasSchema(emailSchema, new HashMap<>()));
     }
 
     /**
      * Issue https://github.com/OpenAPITools/openapi-generator/issues/1624.
-     * ModelUtils.isFreeFormObject() should not throw an NPE when passed an empty
+     * modelUtils.isFreeFormObject() should not throw an NPE when passed an empty
      * object schema that has additionalProperties defined as an empty object schema.
      */
     @Test
     public void testIsFreeFormObject() {
         OpenAPI openAPI = new OpenAPI().openapi("3.0.0");
+        ModelUtils modelUtils = new ModelUtils(openAPI);
+
         // Create initial "empty" object schema.
         ObjectSchema objSchema = new ObjectSchema();
-        Assert.assertTrue(ModelUtils.isFreeFormObject(openAPI, objSchema));
+        Assert.assertTrue(modelUtils.isFreeFormObject(objSchema));
 
         // Set additionalProperties to an empty ObjectSchema.
         objSchema.setAdditionalProperties(new ObjectSchema());
-        Assert.assertTrue(ModelUtils.isFreeFormObject(openAPI, objSchema));
+        Assert.assertTrue(modelUtils.isFreeFormObject(objSchema));
 
         // Add a single property to the schema (no longer a free-form object).
         Map<String, Schema> props = new HashMap<>();
         props.put("prop1", new StringSchema());
         objSchema.setProperties(props);
-        Assert.assertFalse(ModelUtils.isFreeFormObject(openAPI, objSchema));
+        Assert.assertFalse(modelUtils.isFreeFormObject(objSchema));
 
         // Test a non-object schema
-        Assert.assertFalse(ModelUtils.isFreeFormObject(openAPI, new StringSchema()));
+        Assert.assertFalse(modelUtils.isFreeFormObject(new StringSchema()));
 
         // Test a null schema
-        Assert.assertFalse(ModelUtils.isFreeFormObject(openAPI, null));
+        Assert.assertFalse(modelUtils.isFreeFormObject(null));
     }
 
     @Test
@@ -262,8 +276,8 @@ public class ModelUtilsTest {
         ArraySchema as = new ArraySchema()
                 .items(new StringSchema());
         as.setUniqueItems(true);
-
-        Assert.assertTrue(ModelUtils.isSet(as));
+        ModelUtils modelUtils = new ModelUtils(null);
+        Assert.assertTrue(modelUtils.isSet(as));
     }
 
     @Test
@@ -271,19 +285,21 @@ public class ModelUtilsTest {
         ArraySchema as = new ArraySchema()
                 .items(new StringSchema());
         as.setUniqueItems(false);
-
-        Assert.assertFalse(ModelUtils.isSet(as));
+        ModelUtils modelUtils = new ModelUtils(null);
+        Assert.assertFalse(modelUtils.isSet(as));
     }
 
     @Test
     public void testIsSetFailsForNullSchema() {
         ArraySchema as = null;
-        Assert.assertFalse(ModelUtils.isSet(as));
+        ModelUtils modelUtils = new ModelUtils(null);
+        Assert.assertFalse(modelUtils.isSet(as));
     }
 
     @Test
     public void testSimpleRefDecoding() {
-        String decoded = ModelUtils.getSimpleRef("#/components/~01%20Hallo~1Welt");
+        ModelUtils modelUtils = new ModelUtils(null);
+        String decoded = modelUtils.getSimpleRef("#/components/~01%20Hallo~1Welt");
         Assert.assertEquals(decoded, "~1 Hallo/Welt");
     }
 }