Java Swing

1. Better works with NetBeans. You get Swing project wizard.
2. Add to your project (editable in designer) another Swing window.
http://www.java2s.com/Tutorial/Java/0240__Swing/DisplayaJFrameinstance.htm
3. Added window has run static main() method needed for starting Java application so you can safely delete initial file created by project wizard. Since it can't be edited by designer.