Index: src/main/org/codehaus/groovy/classgen/Verifier.java
===================================================================
--- src/main/org/codehaus/groovy/classgen/Verifier.java	(revision 18216)
+++ src/main/org/codehaus/groovy/classgen/Verifier.java	(working copy)
@@ -224,9 +224,9 @@
 
         if (!node.hasMethod("getMetaClass", Parameter.EMPTY_ARRAY)) {
             metaClassField = setMetaClassFieldIfNotExists(node, metaClassField);
-            node.addSyntheticMethod(
+            addMethod(node,!Modifier.isAbstract(node.getModifiers()),
                     "getMetaClass",
-                    ACC_PUBLIC | ACC_SYNTHETIC,
+                    ACC_PUBLIC,
                     ClassHelper.METACLASS_TYPE,
                     Parameter.EMPTY_ARRAY,
                     ClassNode.EMPTY_ARRAY,
@@ -275,7 +275,7 @@
                 setMetaClassCode = new BytecodeSequence(list);
             }
             
-            node.addSyntheticMethod(
+            addMethod(node,!Modifier.isAbstract(node.getModifiers()),
                     "setMetaClass",
                     ACC_PUBLIC,
                     ClassHelper.VOID_TYPE,
@@ -291,7 +291,8 @@
             VariableScope blockScope = new VariableScope();
             blockScope.putReferencedLocalVariable(vMethods);
             blockScope.putReferencedLocalVariable(vArguments);
-            node.addSyntheticMethod(
+
+            addMethod(node,!Modifier.isAbstract(node.getModifiers()),
                     "invokeMethod",
                     ACC_PUBLIC,
                     ClassHelper.OBJECT_TYPE, INVOKE_METHOD_PARAMS,
@@ -311,7 +312,7 @@
         }
 
         if (!node.hasMethod("getProperty", GET_PROPERTY_PARAMS)) {
-            node.addSyntheticMethod(
+        	addMethod(node,!Modifier.isAbstract(node.getModifiers()),
                     "getProperty",
                     ACC_PUBLIC,
                     ClassHelper.OBJECT_TYPE,
@@ -331,7 +332,7 @@
         }
 
         if (!node.hasMethod("setProperty", SET_PROPERTY_PARAMS)) {
-            node.addSyntheticMethod(
+        	addMethod(node,!Modifier.isAbstract(node.getModifiers()),
                     "setProperty",
                     ACC_PUBLIC,
                     ClassHelper.VOID_TYPE,
@@ -351,6 +352,20 @@
         }
     }
 
+    /**
+     * Helper method to add a new method to a ClassNode.  Depending on the shouldBeSynthetic flag the 
+     * call will either be made to ClassNode.addSyntheticMethod() or ClassNode.addMethod(). If a non-synthetic method 
+     * is to be added the ACC_SYNTHETIC modifier is removed if it has been accidentally supplied.
+     */
+    private void addMethod(ClassNode node, boolean shouldBeSynthetic, String name, int modifiers, ClassNode returnType, Parameter[] parameters,
+			ClassNode[] exceptions, Statement code) {
+    	if (shouldBeSynthetic) {
+    		node.addSyntheticMethod(name,modifiers,returnType,parameters,exceptions,code);
+    	} else {
+    		node.addMethod(name,modifiers&~ACC_SYNTHETIC,returnType,parameters,exceptions,code);    		
+    	}
+	}
+
     protected void addTimeStamp(ClassNode node) {
         FieldNode timeTagField = new FieldNode(
                 Verifier.__TIMESTAMP,