Your details are pretty scratchy, but from what I understand and your team lead says the right thing for the job is a HTTP POST, and this is better achieved with httpcomponents from apache.
Some sample code might look like:
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(urlAsString);
HttpResponse rsp = null;
try {
rsp = client.execute(post);
} catch (IOException e) {
//ha ha
} finally {
//close stuff
}
and probably you will need to fetch some token from the response in order to make later request as logged in, but this is a implementation detail.
A pretty good example can be found here: http://www.vogella.com/articles/ApacheHttpClient/article.html
This is from the top of my head, hope it helps.