Short desc:
 Test executes applet in jnlp style, inside applet tries to get codebase:
  1. using Applet.getCodeBase();
  2. using
     BasicService bs = (BasicService)ServiceManager.lookup("javax.jnlp.BasicService");
     bs.getCodeBase();

  Test fails because these two values aren't equal.
  
See applet code source and applet execution log in attachment.
See details, html links in "Comments" section ( How to reproduce ).