I know I’m kinda late by 10 months here. But a good option using Jsoup is to use this easy peasy piece of code:
//This will get you the response.
Response res = Jsoup
.connect("url")
.data("loginField", "login@login.com", "passField", "pass1234")
.method(Method.POST)
.execute();
//This will get you cookies
Map<String, String> cookies = res.cookies();
//And this is the easieste way I've found to remain in session
Documente doc = Jsoup.connect("url").cookies(cookies).get();
Though I’m still having trouble connection to SOME websites, I connect to a whole lot of them with the same basic piece of code. Oh, and before I forget.. What I figured my problem is, is SSL certificates. You have to properly manage them in a way I still haven’t quite figured out.