CODEWITHSUNDEEP
javapropertiesgtklook-and-feel
exhuma
exhuma

Reputation: 21737

NPE When running Netbeans using the GTK LAF

Recently, I got a weird stack trace in the netbeans logs (I added it to the end of this post). I was able to track it down to the LAF. This error happens, when running Netbeans using the GTK LAF, but works fine in Metal, and using the native Windows LAF.

It seems, that the PropertyChangeSupport instance is NULL, so it throws an error when adding a Property change listener. Here's the abbreviated source of my custom component:

public class EnterprisePicker extends javax.swing.JPanel implements ActionListener, KeyListener, ListSelectionListener, UnitContainer {

    private static final Logger logger = IdeUiUtil.initLogger(EnterprisePicker.class.getName());
    protected InfoPanelStyle infoPanelStyle = InfoPanelStyle.FULL;
    private final PropertyChangeSupport propertyChangeSupport = new PropertyChangeSupport(this);
    public static final String PROP_INFOPANELSTYLE = "infoPanelStyle";

    /** Creates the new component */
    public EnterprisePicker() {
        // [... snip ...]
    }

    // [ ... snip ... ]

    /**
     * Add PropertyChangeListener.
     *
     * @param listener
     */
    @Override
    public void addPropertyChangeListener(PropertyChangeListener listener) {
        propertyChangeSupport.addPropertyChangeListener(listener);
    }

    // [ ... snip ... ]

}

Obviously I could simply protect these calls using if (propertyChangeSupport == null)... But would that not break properties later on in the application? Assuming that no listener will ever be attached as the instance is null...?

Stack Trace

INFO [org.netbeans.modules.form.BeanSupport]: Cannot create default instance of: org.statec.ide.ui.components.EnterprisePicker
java.lang.NullPointerException
        at org.statec.ide.ui.components.EnterprisePicker.addPropertyChangeListener(EnterprisePicker.java:654)
        at javax.swing.plaf.synth.SynthPanelUI.installListeners(SynthPanelUI.java:49)
        at javax.swing.plaf.synth.SynthPanelUI.installUI(SynthPanelUI.java:38)
        at javax.swing.JComponent.setUI(JComponent.java:662)
        at javax.swing.JPanel.setUI(JPanel.java:136)
        at javax.swing.JPanel.updateUI(JPanel.java:109)
        at javax.swing.JPanel.<init>(JPanel.java:69)
        at javax.swing.JPanel.<init>(JPanel.java:92)
        at javax.swing.JPanel.<init>(JPanel.java:100)
        at org.statec.ide.ui.components.EnterprisePicker.<init>(EnterprisePicker.java:39)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at java.lang.Class.newInstance0(Class.java:355)
        at java.lang.Class.newInstance(Class.java:308)
        at org.netbeans.modules.form.CreationFactory.createDefaultInstance(CreationFactory.java:168)
[catch] at org.netbeans.modules.form.BeanSupport.createBeanInstance(BeanSupport.java:83)
        at org.netbeans.modules.form.BeanSupport.getDefaultInstance(BeanSupport.java:109)
        at org.netbeans.modules.form.GandalfPersistenceManager.restoreComponent(GandalfPersistenceManager.java:769)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadComponent(GandalfPersistenceManager.java:1007)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadForm(GandalfPersistenceManager.java:527)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadForm(GandalfPersistenceManager.java:299)
        at org.netbeans.modules.form.FormEditor$3.run(FormEditor.java:337)
        at org.netbeans.modules.form.FormLAF$2.run(FormLAF.java:293)
        at org.openide.util.Mutex.doEventAccess(Mutex.java:1361)
        at org.openide.util.Mutex.readAccess(Mutex.java:320)
        at org.netbeans.modules.form.FormLAF.executeWithLookAndFeel(FormLAF.java:276)
        at org.netbeans.modules.form.FormEditor.loadFormData(FormEditor.java:334)
        at org.netbeans.modules.form.FormEditor.loadFormDesigner(FormEditor.java:232)
        at org.netbeans.modules.form.FormDesigner.finishComponentShowing(FormDesigner.java:1932)
        at org.netbeans.modules.form.FormDesigner.access$1100(FormDesigner.java:107)
        at org.netbeans.modules.form.FormDesigner$PreLoadTask$1.run(FormDesigner.java:1897)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
        at java.awt.EventQueue.access$000(EventQueue.java:84)
        at java.awt.EventQueue$1.run(EventQueue.java:602)
        at java.awt.EventQueue$1.run(EventQueue.java:600)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:148)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
INFO
org.openide.ErrorManager$AnnException: msg
        at org.openide.ErrorManager$AnnException.findOrCreate(ErrorManager.java:866)
        at org.openide.ErrorManager$DelegatingErrorManager.annotate(ErrorManager.java:653)
        at org.netbeans.modules.form.GandalfPersistenceManager.annotateException(GandalfPersistenceManager.java:237)
        at org.netbeans.modules.form.GandalfPersistenceManager.annotateException(GandalfPersistenceManager.java:247)
        at org.netbeans.modules.form.GandalfPersistenceManager.restoreComponent(GandalfPersistenceManager.java:865)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadComponent(GandalfPersistenceManager.java:1007)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadForm(GandalfPersistenceManager.java:527)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadForm(GandalfPersistenceManager.java:299)
        at org.netbeans.modules.form.FormEditor$3.run(FormEditor.java:337)
        at org.netbeans.modules.form.FormLAF$2.run(FormLAF.java:293)
        at org.openide.util.Mutex.doEventAccess(Mutex.java:1361)
        at org.openide.util.Mutex.readAccess(Mutex.java:320)
        at org.netbeans.modules.form.FormLAF.executeWithLookAndFeel(FormLAF.java:276)
        at org.netbeans.modules.form.FormEditor.loadFormData(FormEditor.java:334)
        at org.netbeans.modules.form.FormEditor.loadFormDesigner(FormEditor.java:232)
        at org.netbeans.modules.form.FormDesigner.finishComponentShowing(FormDesigner.java:1932)
        at org.netbeans.modules.form.FormDesigner.access$1100(FormDesigner.java:107)
        at org.netbeans.modules.form.FormDesigner$PreLoadTask$1.run(FormDesigner.java:1897)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
        at java.awt.EventQueue.access$000(EventQueue.java:84)
        at java.awt.EventQueue$1.run(EventQueue.java:602)
        at java.awt.EventQueue$1.run(EventQueue.java:600)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:148)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
msg
Caused: java.lang.NullPointerException
        at org.statec.ide.ui.components.EnterprisePicker.addPropertyChangeListener(EnterprisePicker.java:654)
        at javax.swing.plaf.synth.SynthPanelUI.installListeners(SynthPanelUI.java:49)
        at javax.swing.plaf.synth.SynthPanelUI.installUI(SynthPanelUI.java:38)
        at javax.swing.JComponent.setUI(JComponent.java:662)
        at javax.swing.JPanel.setUI(JPanel.java:136)
        at javax.swing.JPanel.updateUI(JPanel.java:109)
        at javax.swing.JPanel.<init>(JPanel.java:69)
        at javax.swing.JPanel.<init>(JPanel.java:92)
        at javax.swing.JPanel.<init>(JPanel.java:100)
        at org.statec.ide.ui.components.EnterprisePicker.<init>(EnterprisePicker.java:39)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
        at java.lang.Class.newInstance0(Class.java:355)
        at java.lang.Class.newInstance(Class.java:308)
        at org.netbeans.modules.form.CreationFactory.createDefaultInstance(CreationFactory.java:168)
        at org.netbeans.modules.form.RADComponent.createBeanInstance(RADComponent.java:252)
        at org.netbeans.modules.form.RADComponent.initInstance(RADComponent.java:191)
        at org.netbeans.modules.form.GandalfPersistenceManager.restoreComponent(GandalfPersistenceManager.java:851)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadComponent(GandalfPersistenceManager.java:1007)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadForm(GandalfPersistenceManager.java:527)
        at org.netbeans.modules.form.GandalfPersistenceManager.loadForm(GandalfPersistenceManager.java:299)
        at org.netbeans.modules.form.FormEditor$3.run(FormEditor.java:337)
        at org.netbeans.modules.form.FormLAF$2.run(FormLAF.java:293)
        at org.openide.util.Mutex.doEventAccess(Mutex.java:1361)
        at org.openide.util.Mutex.readAccess(Mutex.java:320)
        at org.netbeans.modules.form.FormLAF.executeWithLookAndFeel(FormLAF.java:276)
        at org.netbeans.modules.form.FormEditor.loadFormData(FormEditor.java:334)
[catch] at org.netbeans.modules.form.FormEditor.loadFormDesigner(FormEditor.java:232)
        at org.netbeans.modules.form.FormDesigner.finishComponentShowing(FormDesigner.java:1932)
        at org.netbeans.modules.form.FormDesigner.access$1100(FormDesigner.java:107)
        at org.netbeans.modules.form.FormDesigner$PreLoadTask$1.run(FormDesigner.java:1897)
        at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
        at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:641)
        at java.awt.EventQueue.access$000(EventQueue.java:84)
        at java.awt.EventQueue$1.run(EventQueue.java:602)
        at java.awt.EventQueue$1.run(EventQueue.java:600)
        at java.security.AccessController.doPrivileged(Native Method)
        at java.security.AccessControlContext$1.doIntersectionPrivilege(AccessControlContext.java:87)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:611)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:148)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)
Error in loading component: [JDialog]->enterprisePicker1
Cannot create instance of org.statec.ide.ui.components.EnterprisePicker.
The component cannot be loaded.

And for reference:

malbert@dredg:~/.netbeans/7.0/var/log$ java -version
java version "1.6.0_26"
Java(TM) SE Runtime Environment (build 1.6.0_26-b03)
Java HotSpot(TM) Server VM (build 20.1-b02, mixed mode)

malbert@dredg:~/.netbeans/7.0/var/log$ cat /etc/lsb-release 
DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=11.04
DISTRIB_CODENAME=natty
DISTRIB_DESCRIPTION="Ubuntu 11.04"

Upvotes: 1

Views: 388

Answers (1)

Thomas
Thomas

Reputation: 88727

Just a guess, but the problem could be that during initialization of some super class addPropertyChangeListener(...) is called (javax.swing.JPanel.<init> might be the culprit), thus this call happens before propertyChangeSupport is initialized.

The initialization sequence of instance fields would be:

  • Object
  • Component
  • Container
  • JComponent
  • JPanel
  • EnterprisePicker

If during initialization of JPanel the addPropertyChangeListener(...) method is called, it would actually be the overridden version of EnterprisePicker, but EnterprisePicker's fields would not have been initialized yet.

To fix this you'd check for null in that method and initialize as needed (or call super.addPropertyChangeListener(...). Is there any need to have your own implementation (to add your own PropertyChangeSupport)?

Upvotes: 3

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