Thread: An internal error occurred during: "Launching ... " java.lang.NullPointerException HELP!!!

Hello,
i'm developping a server-client application.

sometimes when i launch my Jframe/JDialog... i get the following error:

An internal error occurred during: "Launching xxxx".
java.lang.NullPointerException

actually i get this error while lauchning the same program i launched without a problem before.
what i do, is that i keep trying, stopping-clearing-restarting my server (wich have certainely nothing to do with it) until it works...

i don't get it and it's really frustrating, i even created a new jframe with absolutely no code in it, just:

public class test extends JFrame {

private JPanel contentPane;

/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
test frame = new test();
frame.setVisible(true);
} catch (Exception e) {
e.printStackTrace();
}
}
});
}

/**
* Create the frame.
*/
public test() {
setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
setBounds(100, 100, 450, 300);
contentPane = new JPanel();
contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
contentPane.setLayout(new BorderLayout(0, 0));
setContentPane(contentPane);
}

}

tried to launch it and had the same problem

did any one had the same problem before?

Search java.lang.NullPointerException so you understand what it means.
Then read the remaining of the error message (which you should post if you still need help) to see where the problem occurred.
Please use code tags when posting code. See the Announcements page if you need help.

--- Update ---

...and Welcome to the forum.