Name: vsC58871 Date: 08/27/98


com.sun.java.swing.JMenu's method remove(JMenuItem mi)
throws NullPointerException if any Action is added to JMenu.

NullPointerException is thrown from this code:

if (listenerRegistry != null) {
    ActionChangedListener p = (ActionChangedListener)listenerRegistry.remove(item);
    Action a = (Action)listenerRegistry.remove(p);
  ...

when item is a JMenuItem, so p = null and
attempt to remove null from listenerRegistry causes NPE.

Here is the example demonstrating the bug:
----------------Test.java---------------------
import com.sun.java.swing.*;
import java.awt.event.*;
import java.beans.*;

public class Test {
    public static void main(String[] args){
JMenu menu = new JMenu();
JMenuItem mi = new JMenuItem("VVS");
Action a = new StubAction();
menu.add(a);
menu.add(mi);
menu.remove(mi); // <--------------
System.exit(0);
    }
}
class StubAction implements Action {
    String name = "StubAction";
    public void actionPerformed(ActionEvent e) {}
    public String getText(String key) { return "StubAction"; }
    public void setText(String key, String newValue) {}
    public Icon getIcon(String key) { return null; }
    public void setIcon(String key, Icon newValue) {}
    public boolean isEnabled() { return true; }
    public void setEnabled(boolean newValue) {}
    public void addPropertyChangeListener(PropertyChangeListener listener) {}
    public void removePropertyChangeListener(PropertyChangeListener listener) {}
    public void putValue(String str, Object o) {}
    public Object getValue(String str) {
if(str.equals(Action.NAME))
return name;
else
return null;
    }
}
-- The output ----------------
#>java -version
java version "1.2fcs"
Classic VM (build JDK-1.2fcs-G, green threads, sunwjit)
#>JAVA_COMPILER=none java Test
Warning: JIT compiler "none" not found. Will use interpreter.
Exception in thread "main" java.lang.NullPointerException
        at java.util.Hashtable.remove(Hashtable.java:421)
        at com.sun.java.swing.JMenu.remove(JMenu.java:581)
        at Test.main(Test.java:12)
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