#fixed code
                                private void requestThenAssertResponse() throws Exception {
        requestThenAssertResponse(remotingClient);
    }
#vulnerable code 
                                private void requestThenAssertResponse() throws Exception {
        RemotingCommand response = remotingClient.invokeSync("localhost:8888", createRequest(), 1000 * 3);
        assertTrue(response != null);
        assertThat(response.getLanguage()).isEqualTo(LanguageCode.JAVA);
        assertThat(response.getExtFields()).hasSize(2);
        assertThat(response.getExtFields().get("messageTitle")).isEqualTo("Welcome");
    } 
                            #location 4 
                            #vulnerability type NULL_DEREFERENCE