NetBeans jFrames not working (just showing loading...)

Question

I created a new project in Netbeans IDE 7.0.1. In that project I created a new JFrame form. But that frame is not loading.

Then I tried to run the program anyway and it gave the following exceptions:

Exception in thread "AWT-EventQueue-0" java.lang.RuntimeException: 
  Uncompilable source code - package org.jdesktop.layout does not exist
at login.initComponents(login.java:33)
at login.<init>(login.java:20)
at login$1.run(login.java:78)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:733)
at java.awt.EventQueue.access$200(EventQueue.java:103)
at java.awt.EventQueue$3.run(EventQueue.java:694)
at java.awt.EventQueue$3.run(EventQueue.java:692)
at java.security.AccessController.doPrivileged(Native Method)
at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:703)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)

I am using Ubuntu 12.10

Answer 1

Looks like you have to add the Swing Layout Extensions Library to your project, to do so go to the Projects explorer, do right-click on Libraries > Add Library... and select Swing Layout Extensions Library. Problem solved.

BTW this is a Duplicate from https://stackoverflow.com/questions/19304700/netbeans-jframes-do-not-work

Answer 2

Example:

import javax.swing.JFrame;
import javax.swing.SwingUtilities;

public class App {

public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable(){
        public void run(){
            JFrame frame = new JFrame("Hello world");

            frame.setVisible(true);
            frame.setSize(600,500);
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        }
    });
}

}