public void handle(HttpRequest request, HttpResponse response, HttpContext context) throws HttpException, IOException {
        Header headerToTest = request.getFirstHeader(ModifyHeadersProxyServlet.REQUEST_HEADER);
        assertEquals("REQUEST_VALUE_MODIFIED", headerToTest.getValue());

        super.handle(request, response, context);
      }
tests to show that by extending ProxyServlet we can override methods coping headers to proxied response and from it
src/test/java/org/mitre/dsmiley/httpproxy/ModifyHeadersProxyServletTest.java