bugfix: issue-4051

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/AbstractJavaCodegen.java

@@ -363,6 +363,10 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
             return name;
         }
 
+        if(startsWithTwoUppercaseLetters(name)){
+            name = name.substring(0, 2).toLowerCase() + name.substring(2);
+        }
+
         // camelize (lower first character) the variable name
         // pet_id => petId
         name = camelize(name, true);
@@ -375,6 +379,14 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         return name;
     }
 
+    private boolean startsWithTwoUppercaseLetters(String name) {
+        boolean startsWithTwoUppercaseLetters = false;
+        if(name.length() > 1) {
+            startsWithTwoUppercaseLetters = name.substring(0, 2).equals(name.substring(0, 2).toUpperCase());
+        }
+        return startsWithTwoUppercaseLetters;
+    }
+
     @Override
     public String toParamName(String name) {
         // to avoid conflicts with 'callback' parameter for async call
@@ -935,8 +947,4 @@ public abstract class AbstractJavaCodegen extends DefaultCodegen implements Code
         return sb.toString();
     }
 
-    public String toRegularExpression(String pattern) {
-        return escapeText(pattern);
-    }
-
 }

modules/swagger-codegen/src/test/java/io/swagger/codegen/java/JavaModelTest.java

@@ -360,6 +360,32 @@ public class JavaModelTest {
         Assert.assertTrue(property.isNotContainer);
     }
 
+    @Test(description = "convert a model starting with two upper-case letter property names")
+    public void firstTwoUpperCaseLetterNamesTest() {
+        final Model model = new ModelImpl()
+                .description("a model with a property name starting with two upper-case letters")
+                .property("ATTName", new StringProperty())
+                .required("ATTName");
+        final DefaultCodegen codegen = new JavaClientCodegen();
+        final CodegenModel cm = codegen.fromModel("sample", model);
+
+        Assert.assertEquals(cm.name, "sample");
+        Assert.assertEquals(cm.classname, "Sample");
+        Assert.assertEquals(cm.vars.size(), 1);
+
+        final CodegenProperty property = cm.vars.get(0);
+        Assert.assertEquals(property.baseName, "ATTName");
+        Assert.assertEquals(property.getter, "getAtTName");
+        Assert.assertEquals(property.setter, "setAtTName");
+        Assert.assertEquals(property.datatype, "String");
+        Assert.assertEquals(property.name, "atTName");
+        Assert.assertEquals(property.defaultValue, "null");
+        Assert.assertEquals(property.baseType, "String");
+        Assert.assertNull(property.hasMore);
+        Assert.assertTrue(property.required);
+        Assert.assertTrue(property.isNotContainer);
+    }
+
     @Test(description = "convert hyphens per issue 503")
     public void hyphensTest() {
         final Model model = new ModelImpl()