#vulnerable code 
                                public void testResponseContentNoEntity() throws Exception {
        HttpContext context = new HttpExecutionContext(null);
        HttpResponse response = new BasicHttpResponse(HttpVersion.HTTP_1_1, HttpStatus.SC_OK, "OK");
        ResponseContent interceptor = new ResponseContent();
        interceptor.process(response, context);
        Header header = response.getFirstHeader(HTTP.CONTENT_LEN);
        assertNotNull(header);
        assertEquals("0", header.getValue());
    } 
                            #location 8 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                public void testResponseContentNoEntity() throws Exception {
        HttpContext context = new BasicHttpContext(null);
        HttpResponse response = new BasicHttpResponse(HttpVersion.HTTP_1_1, HttpStatus.SC_OK, "OK");
        ResponseContent interceptor = new ResponseContent();
        interceptor.process(response, context);
        Header header = response.getFirstHeader(HTTP.CONTENT_LEN);
        assertNotNull(header);
        assertEquals("0", header.getValue());
    }