code: static boolean isMutable(Class<?> clazz)
      {
          if (clazz.isPrimitive())
              return false;
  
          if (clazz == String.class)
              return false;
          if (clazz == Boolean.class)
              return false;
          if (clazz == Character.class)
              return false;
          if (clazz == Byte.class)
              return false;
          if (clazz == Short.class)
              return false;
          if (clazz == Integer.class)
              return false;
          if (clazz == Long.class)
              return false;
          if (clazz == Float.class)
              return false;
          if (clazz == Double.class)
              return false;
  
          return true;
      }
docs: Returns true if the state of an instance of the specified class may
  be modified after the instance has been created. <p>
  
  Returns false for the pimitives, primitive wrapper classes, and
  Sring. <p>
  
  This method is useful when generating the 'local' optimization code
  for a stub, as only 'mutable' objects must be copied. <p>
  
  @param clazz class to check for mutability.