code: @Override
      public void overrideMethod(ClassMethod method, Method superclassMethod) {
          CodeAttribute ca = method.getCodeAttribute();
          Class<?> returnType = superclassMethod.getReturnType();
          if (!returnType.isPrimitive()) {
              ca.aconstNull();
          } else if (returnType == double.class) {
              ca.dconst(0);
          } else if (returnType == float.class) {
              ca.fconst(0);
          } else if (returnType == long.class) {
              ca.lconst(0);
          } else if (returnType == void.class) {
              // do nothing
          } else {
              ca.iconst(0);
          }
          ca.returnInstruction();
      }
docs: {@inheritDoc}