#vulnerable code 
                             @Test
	public void testGetFields() throws JSONException, UnirestException {
		HttpResponse<JsonNode> response = Unirest.get("http://httpbin.org/get").queryString("name", "mark").queryString("nick", "thefosk").asJson();
		assertEquals(response.getBody().getObject().getJSONObject("args").getString("name"), "mark");
		assertEquals(response.getBody().getObject().getJSONObject("args").getString("nick"), "thefosk");
	} 
                            #location 4 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                             @Test
	public void testGetFields() throws JSONException, UnirestException {
		HttpResponse<JsonNode> response = Unirest.get(MockServer.GETJSON)
                .queryString("name", "mark")
                .queryString("nick", "thefosk")
                .asJson();

        RequestCapture parse = parse(response);
        parse.assertQuery("name", "mark");
		parse.assertQuery("nick", "thefosk");
	}