@SuppressWarnings("Unchecked") public static Object checkImmutable(Class<?> clazz, String fieldName, Object field) { Immutable immutable = (Immutable) clazz.getAnnotation(MY_CLASS); List<Class> knownImmutableClasses = new ArrayList<Class>(); if (immutable != null && immutable.knownImmutableClasses().length > 0) { knownImmutableClasses = Arrays.asList(immutable.knownImmutableClasses()); } if (field == null || field instanceof Enum || inImmutableList(field.getClass().getName()) || knownImmutableClasses.contains(field.getClass())) return field; if (field instanceof Collection) return DefaultGroovyMethods.asImmutable((Collection) field); if (field.getClass().getAnnotation(MY_CLASS) != null) return field; final String typeName = field.getClass().getName(); throw new RuntimeException( createErrorMessage(clazz.getName(), fieldName, typeName, "constructing")); }