output: #fixed code
                               @Test
  	public void testCustomUserAgent() throws JSONException, UnirestException {
  		HttpResponse<JsonNode> response = Unirest.get(MockServer.GETJSON)
                  .header("user-agent", "hello-world")
                  .asJson();
  
          RequestCapture json = parse(response);
          json.assertHeader("User-Agent", "hello-world");
  	}
input: #vulnerable code 
                               @Test
  	public void testCustomUserAgent() throws JSONException, UnirestException {
  		HttpResponse<JsonNode> response = Unirest.get("http://httpbin.org/get?name=mark").header("user-agent", "hello-world").asJson();
  		assertEquals("hello-world", response.getBody().getObject().getJSONObject("headers").getString("User-Agent"));
  
  		GetRequest getRequest = Unirest.get("http");
  		for (Object current : Arrays.asList(0, 1, 2)) {
  			getRequest.queryString("name", current);
  		}
  
  	} 
                              #location 4 
                              #vulnerability type NULL_DEREFERENCE