title: GPLv2 components in Java applets
body: <p>I have a java application which basicaly consists of three things:</p>
  
  <ul>
  <li>application core</li>
  <li>web ui</li>
  <li>java applet</li>
  </ul>
  
  <p>Using web ui, users launch java applet to access services provided by application core.
  The application is hosted on my servers.</p>
  
  <p>What if i take source code of another java applet, licensed under GPLv2 and integrate it in my applet, to provide additional feature. I also tweak the source code slightly to provide better integration with my applet and application core.</p>
  
  <p>Do i have to release my whole applet's source code under GPL license or just the modified files?
  And when and how should i do that? 
  Should i bundle the modified source code in applet jar?</p>
  
  <p>Will there be any difference if:</p>
  
  <ul>
  <li>people use this service for free</li>
  <li>people pay for this service</li>
  <li>i sell my whole application as closed source product to people</li>
  </ul>
  
  <p><strong>Edit 1:</strong></p>
  
  <ul>
  <li>application is sold to people. Core - closed source, Applet - GPL`ed, with source code.</li>
  </ul>
  
  <p>The integrated applet can be considered as a module of the main applet - do i still have to provide source code of the whole applet or just the module?</p>
  
  <p>Also, what if i use gpl'ed applet as a library/jar without modification?</p>