diff --git a/docs/generators/csharp.md b/docs/generators/csharp.md
index c3b17808dc7..102af5dbb07 100644
--- a/docs/generators/csharp.md
+++ b/docs/generators/csharp.md
@@ -88,6 +88,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>List</li>
 <li>Object</li>
 <li>String</li>
+<li>System</li>
 <li>System.IO.Stream</li>
 <li>bool</li>
 <li>bool?</li>
diff --git a/docs/generators/java.md b/docs/generators/java.md
index 941e1c4e2ea..db3cb37efc1 100644
--- a/docs/generators/java.md
+++ b/docs/generators/java.md
@@ -197,7 +197,9 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>int</li>
 <li>interface</li>
 <li>list</li>
+<li>localdate</li>
 <li>localreturntype</li>
+<li>localtime</li>
 <li>localvaraccept</li>
 <li>localvaraccepts</li>
 <li>localvarauthnames</li>
@@ -215,6 +217,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 <li>new</li>
 <li>null</li>
 <li>object</li>
+<li>offsetdatetime</li>
 <li>package</li>
 <li>private</li>
 <li>protected</li>
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 fac84740841..aa8dda7151c 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
@@ -146,7 +146,7 @@ public abstract class AbstractCSharpCodegen extends DefaultCodegen implements Co
                         "foreach", "goto", "if", "implicit", "in", "int", "interface", "internal", "is", "lock",
                         "long", "namespace", "new", "null", "object", "operator", "out", "override", "params",
                         "private", "protected", "public", "readonly", "ref", "return", "sbyte", "sealed",
-                        "short", "sizeof", "stackalloc", "static", "string", "struct", "switch", "this", "throw",
+                        "short", "sizeof", "stackalloc", "static", "string", "struct", "switch", "system", "this", "throw",
                         "true", "try", "typeof", "uint", "ulong", "unchecked", "unsafe", "ushort", "using",
                         "virtual", "void", "volatile", "while")
         );
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 9dae2c164ba..fa9a016d1d3 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
@@ -196,7 +196,7 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
                         "import", "public", "throws", "case", "enum", "instanceof", "return", "transient",
                         "catch", "extends", "int", "short", "try", "char", "final", "interface", "static",
                         "void", "class", "finally", "long", "strictfp", "volatile", "const", "float",
-                        "native", "super", "while", "null")
+                        "native", "super", "while", "null", "offsetdatetime", "localdate", "localtime")
         );
 
         languageSpecificPrimitives = Sets.newHashSet("String",