Re: Java application can hang when accessing the screen menu bar in 32-bit Java6

Subject: Re: Java application can hang when accessing the screen menu bar in 32-bit Java6
From: Doug Zwick <email@hidden>
Date: Mon, 14 Sep 2009 12:02:51 -0600
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Michael Ellis wrote:

I've encountered a serious problem with Snow Leopard Java 6, and I
wanted to make you all aware of it.  If you experience a similar
issue, please vote for the resolution of this bug by submitting your
own report at http://bugreport.apple.com.


The top few frames of this trace look familiar:

AWT Thread: "AWT-EventQueue-0" prio=6 tid=0x01953800 nid=0xb2342000 runnable [0xb2341000] java.lang.Thread.State: RUNNABLE at apple.awt.CGlobalCursorManager.findHeavyweightUnderCursor(Native Method) at apple .awt.CGlobalCursorManager._updateCursor(CGlobalCursorManager.java:130) at apple .awt .CGlobalCursorManager .updateCursorImmediately(CGlobalCursorManager.java:75) at apple.awt.ComponentModel.updateCursorImmediately(ComponentModel.java: 166) at java.awt.Component.updateCursorImmediately(Component.java:2919) at java.awt.Component.hide(Component.java:1608) - locked <0x04a5c970> (a java.awt.Component$AWTTreeLock) at java.awt.Component.show(Component.java:1565) at java.awt.Component.setVisible(Component.java:1515) at javax.swing.JComponent.setVisible(JComponent.java:2612) at com.merlinone.merlin.client.views.MOMCWorkspaceFooterController $_ProgressBarUpdater$1.run(MOMCWorkspaceFooterController.java:587) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209) at java.awt.EventQueue.dispatchEvent(EventQueue.java:633) at java .awt .EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java: 296) at java .awt .EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:211) at java .awt .EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java: 201) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java: 196) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java: 188) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)

I have seen "findHeavyweightUnderCursor" implicated in deadlocks back to OS X 10.4 and Java 1.5. I was never able to reproduce the deadlock (it only happened very rarely), and was never sure that that was really the problem. What I discovered from tracing the hung processes is that findHeavyweightUnderCursor calls NSObject performSelectorOnMainThread with waitUntilDone=YES. This blocks the Swing thread against the AppKit thread. If anything unexpected happens on the AppKit thread to prevent it from servicing the selector in a timely manner, it can deadlock. I wish I still had those traces. _______________________________________________ Do not post admin requests to the list. They will be ignored. Java-dev mailing list (email@hidden) Help/Unsubscribe/Update your Subscription: This email sent to email@hidden Prev by Date: Re: Menu strangeness Next by Date: Re: Slightly OT Java / Mac Pro performance question - looking for advice. Previous by thread: Java application can hang when accessing the screen menu bar in 32-bit Java6 Next by thread: Snow Leopard and Rosetta Index(es): Date Thread Home Archives Terms/Conditions Contact RSS Lists About Visit the Apple Store online or at retail locations. 1-800-MY-APPLE Contact Apple | Terms of Use | Privacy Policy Copyright © 2011 Apple Inc. All rights reserved.