title: How to Support JFrame transparency on Linux
body: <p>I'm making a java swing application which is executed on linux machine and shown in users' computer by X11 forwarding.<br>
  <br>
  I want to apply rounded corners on JFrame, so I changed its background to new Color(0,0,0,0).<br>
  The frame is now hidden on my computer(windows 10). But the linux(centOS7) doesn't seem not to support Window Frame transparency.<br>
  <br>
  It returns error below.<br></p>
  
  <pre><code>    Exception in thread "AWT-EventQueue-0" 
      java.lang.UnsupportedOperationException: PERPIXEL_TRANSLUCENT translucency is not supported
      at java.awt.Window.setBackground(Window.java:3844)
      at java.awt.Frame.setBackground(Frame.java:988)
  </code></pre>
  
  <p>Without changing its background works fine on both but the default background is also shown.<br>
  Is there any way to make rounded corners??<br>
  Thank you.</p>