Code in the GrayBoxPainter class which doesn't obey the AWT threading model is causing some applets to hang. The following (implicit, not explicit) deadlock, excerpted from the attached thread dump, is quite easily reproduced by running the SwingSet2 applet from http://java.sun.com/products/plugin/1.5.0/demos/plugin/jfc/SwingSet2/SwingSet2.html with the Java Console enabled.

In order to fix this, GrayBoxPainter.suspendPainting() and likely any other of the GrayBoxPainter's methods must be brought in line with the AWT threading model.

"Thread-24" prio=4 tid=0x03230c00 nid=0x358 waiting for monitor entry [0x0ec1f000..0x0ec1fc94]
   java.lang.Thread.State: BLOCKED (on object monitor)
at java.awt.Component.setFont(Unknown Source)
- waiting to lock <0x22eb90c8> (a java.awt.Component$AWTTreeLock)
at java.awt.Container.setFont(Unknown Source)
at javax.swing.JComponent.setFont(Unknown Source)
at javax.swing.LookAndFeel.installColorsAndFont(Unknown Source)
at javax.swing.plaf.basic.BasicPanelUI.installDefaults(Unknown Source)
at javax.swing.plaf.basic.BasicPanelUI.installUI(Unknown Source)
at javax.swing.JComponent.setUI(Unknown Source)
at javax.swing.JPanel.setUI(Unknown Source)
at javax.swing.JPanel.updateUI(Unknown Source)
at javax.swing.JPanel.<init>(Unknown Source)
at javax.swing.JPanel.<init>(Unknown Source)
at javax.swing.JPanel.<init>(Unknown Source)
at javax.swing.JRootPane.createGlassPane(Unknown Source)
at javax.swing.JRootPane.<init>(Unknown Source)
at javax.swing.JApplet.createRootPane(Unknown Source)
at javax.swing.JApplet.<init>(Unknown Source)
at DemoModule.<init>(DemoModule.java:107)
at ButtonDemo.<init>(ButtonDemo.java:108)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
at sun.reflect.NativeConstructorAccessorImpl.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(Unknown Source)
at java.lang.reflect.Constructor.newInstance(Unknown Source)
at SwingSet2.loadDemo(SwingSet2.java:822)
at SwingSet2.loadDemos(SwingSet2.java:95)
at SwingSet2$DemoLoadThread.run(SwingSet2.java:1410)

"thread applet-SwingSet2Applet-4" prio=4 tid=0x02a8b400 nid=0x4b8 in Object.wait() [0x0daff000..0x0daffa94]
   java.lang.Thread.State: WAITING (on object monitor)
at java.lang.Object.wait(Native Method)
at java.lang.Object.wait(Object.java:485)
at javax.swing.text.AbstractDocument.readLock(Unknown Source)
- locked <0x244d6908> (a javax.swing.text.PlainDocument)
at javax.swing.plaf.basic.BasicTextUI.getPreferredSize(Unknown Source)
at javax.swing.JComponent.getPreferredSize(Unknown Source)
at javax.swing.JTextField.getPreferredSize(Unknown Source)
at java.awt.BorderLayout.layoutContainer(Unknown Source)
- locked <0x22eb90c8> (a java.awt.Component$AWTTreeLock)
at java.awt.Container.layout(Unknown Source)
at java.awt.Container.doLayout(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validateTree(Unknown Source)
at java.awt.Container.validate(Unknown Source)
- locked <0x22eb90c8> (a java.awt.Component$AWTTreeLock)
at sun.plugin.util.GrayBoxPainter.suspendPainting(Unknown Source)
- locked <0x244955d8> (a sun.plugin.util.GrayBoxPainter)
at sun.plugin2.applet.Plugin2Manager$AppletExecutionRunnable.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)

"AWT-EventQueue-5" prio=4 tid=0x032af800 nid=0x360 waiting for monitor entry [0x0e5ff000..0x0e5ffb14]
   java.lang.Thread.State: BLOCKED (on object monitor)
at java.awt.Component.invalidate(Unknown Source)
- waiting to lock <0x22eb90c8> (a java.awt.Component$AWTTreeLock)
at java.awt.Container.invalidate(Unknown Source)
at javax.swing.JComponent.revalidate(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI$RootView.preferenceChanged(Unknown Source)
at javax.swing.text.View.preferenceChanged(Unknown Source)
at javax.swing.text.PlainView.updateDamage(Unknown Source)
at javax.swing.text.PlainView.insertUpdate(Unknown Source)
at javax.swing.text.FieldView.insertUpdate(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI$RootView.insertUpdate(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI$UpdateHandler.insertUpdate(Unknown Source)
at javax.swing.text.AbstractDocument.fireInsertUpdate(Unknown Source)
at javax.swing.text.AbstractDocument.handleInsertString(Unknown Source)
at javax.swing.text.AbstractDocument.insertString(Unknown Source)
at javax.swing.text.PlainDocument.insertString(Unknown Source)
at javax.swing.text.AbstractDocument.replace(Unknown Source)
at javax.swing.text.JTextComponent.setText(Unknown Source)
at SwingSet2$5.run(SwingSet2.java:937)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)

"AWT-EventQueue-1" prio=6 tid=0x0312a800 nid=0x2c8 waiting for monitor entry [0x035cf000..0x035cfb94]
   java.lang.Thread.State: BLOCKED (on object monitor)
at java.awt.Component.invalidate(Unknown Source)
- waiting to lock <0x22eb90c8> (a java.awt.Component$AWTTreeLock)
at java.awt.Container.invalidate(Unknown Source)
at javax.swing.JComponent.revalidate(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI$RootView.preferenceChanged(Unknown Source)
at javax.swing.text.View.preferenceChanged(Unknown Source)
at javax.swing.text.PlainView.updateDamage(Unknown Source)
at javax.swing.text.PlainView.insertUpdate(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI$RootView.insertUpdate(Unknown Source)
at javax.swing.plaf.basic.BasicTextUI$UpdateHandler.insertUpdate(Unknown Source)
at javax.swing.text.AbstractDocument.fireInsertUpdate(Unknown Source)
at javax.swing.text.AbstractDocument.handleInsertString(Unknown Source)
at javax.swing.text.AbstractDocument.insertString(Unknown Source)
at javax.swing.text.PlainDocument.insertString(Unknown Source)
at javax.swing.JTextArea.append(Unknown Source)
at com.sun.deploy.util.ConsoleWindow$25.run(Unknown Source)
at java.awt.event.InvocationEvent.dispatch(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)