title: Java swing close icon
body: <p>I would like to create a close button. For this, I need a <code>close</code> icon, which I would like to get from the current UI style. I've found a function for this: <code>UIManager.getIcon(key)</code></p>
  
  <p>The only problem is, that I don't know any key. I have no idea, how to get a <code>close</code> icon.</p>