#vulnerable code 
                                @Test
    public void testGetQuerystringArray() throws JSONException, UnirestException {
        HttpResponse<JsonNode> response = Unirest.get("http://httpbin.org/get").queryString("name", "Mark").queryString("name", "Tom").asJson();

        JSONArray names = response.getBody().getObject().getJSONObject("args").getJSONArray("name");
        assertEquals(2, names.length());

        assertEquals("Mark", names.getString(0));
        assertEquals("Tom", names.getString(1));
    } 
                            #location 5 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                @Test
    public void testGetQuerystringArray() throws JSONException, UnirestException {
        HttpResponse<JsonNode> response = Unirest.get(MockServer.GET)
                .queryString("name", "Mark")
                .queryString("name", "Tom")
                .asJson();

        parse(response)
                .assertParam("name", "Mark")
                .assertParam("name", "Tom");
    }