NullPointerException in DropTarget.addNotify()

DropTarget.addNotify(peer) throws NullPointerException in case of (peer==null). It breaks compatibility of our applications switching to jdk1.4

Note that our applications use nothing from java.awt.dnd package and the problem appears just for jdk1.4.

java version "1.4.0-beta"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-beta-b64)
Java HotSpot(TM) Client VM (build 1.4.0-beta-b64, mixed mode)

java.lang.NullPointerException
        at java.awt.dnd.DropTarget.addNotify(DropTarget.java:457)
        at java.awt.Component.addNotify(Component.java:5271)
        at java.awt.Container.addNotify(Container.java:1949)
        at javax.swing.JComponent.addNotify(JComponent.java:4141)
        at java.awt.Container.addNotify(Container.java:1957)
        at javax.swing.JComponent.addNotify(JComponent.java:4141)
        at java.awt.Container.addNotify(Container.java:1957)
        at javax.swing.JComponent.addNotify(JComponent.java:4141)
        at javax.swing.JRootPane.addNotify(JRootPane.java:664)


-----------------------
We use imaginary frame for printing of html documents. The frame has no peer to avoid its displaing on screen. This is demo code (it uses other frame for printing document instaed of real printer):


public class JHFrame extends JFrame {

    public void addNotify() {
        getRootPane().addNotify();
    }

    public void validate() {
        validateTree();
    }

    public static void main(String args[]) {
        try {
            JEditorPane editor = new JEditorPane("http://java.sun.com");
            
            Thread.sleep(1000); // waiting for page download and render
                        
            JFrame frame = new JHFrame();
            frame.setContentPane(editor);
            frame.setBounds(0, 0, 200, 200);
            frame.setVisible(true);
            
            JFrame view = new JFrame("Printing frame");
            view.setBounds(0, 200, 200, 200);
            view.setVisible(true);
            
            editor.paint(view.getGraphics());
            
        } catch (Exception e) {
            e.printStackTrace();
            System.exit(0);
        }
    }
}

This code works on jdk1.3 but not on jdk1.4.

stepan.marek@czech 2001-05-24

I've modified Stepan's code slightly because it didn't work in my environment. I've attached the modification. To execute:

java JHFrame jws.html

Note: This is probably due to the DnD additions to the JEditorPane since the DnD code never changed.

roger.brinkley@Eng 2001-05-24

Update the attachemnts


roger.brinkley@Eng 2001-05-24