Solution :
You have the code of your own program that you have not yet shown to us, likely in the ActionListener or in the method that one of the ActionListener's calls, that usually throws such an exception. So you need to find it, and fix it as simple as that.
As noted by many of the exception's own the Stacktrace message will always tell you what lines are causing you the exception, but again, I am very sure that it will be in the method that has been created by the NetBeans and that looks something like the below one:
// The X shown below is some number
private void jButtonXActionPerformed(java.awt.event.ActionEvent evt) { throws new UnsupportedOperationException("Not supported yet.");}
To fix this error you just need to remove your throws statement and instead of that you just need to add the code that should be called when your button is pressed.
This method of solving the error have helped many coders to fix there toughest of errors in minimum time.
