code: @Test public void testInvalidConstructor(){
    HttpParams params=new BasicHttpParams();
    SessionInputBuffer inbuf=new SessionInputBufferImpl(1024,128,params);
    try {
      new DefaultHttpRequestParser(null,null,null,params);
      Assert.fail("IllegalArgumentException should have been thrown");
    }
   catch (  IllegalArgumentException ex) {
    }
    try {
      new DefaultHttpRequestParser(inbuf,null,null,params);
      Assert.fail("IllegalArgumentException should have been thrown");
    }
   catch (  IllegalArgumentException ex) {
    }
    try {
      new DefaultHttpResponseParser(null,null,null,params);
      Assert.fail("IllegalArgumentException should have been thrown");
    }
   catch (  IllegalArgumentException ex) {
    }
    try {
      new DefaultHttpResponseParser(inbuf,null,null,params);
      Assert.fail("IllegalArgumentException should have been thrown");
    }
   catch (  IllegalArgumentException ex) {
    }
  }
  