Date: Thu, 18 May 2000 22:25:00 -0600 (MDT) From: Nate Williams <nate@yogotech.com> To: Sean Reilly <sreilly@seanreilly.com> Cc: freebsd-java@FreeBSD.ORG Subject: Re: problem in 1.1.8 Message-ID: <200005190425.WAA28735@nomad.yogotech.com> In-Reply-To: <Pine.BSF.4.10.10005181934260.61564-100000@seanreilly.com> References: <Pine.BSF.4.10.10005181934260.61564-100000@seanreilly.com>
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> I'm running into a problem on 4.0-RELEASE with the 1.1.8 JDK port. My
> program freezes shortly after startup while trying to load an image as a
> splash window. Hitting Ctrl-\ results in the thread dump below. Is the
> X11Graphics.finalize supposed to be called from within String.<init> or am
> I reading this wrong?
"finalize" should *NEVER* be called from external threads, and is the
domain of the GC thread. Are you calling finalize by hand?
> Any insight as to how I can avoid this is appreciated.
See above. How are you loading the image? Can you give a bit more
details as to what exactly the program is doing.
> ^\SIGQUIT 3* quit
>
> Full thread dump:
> sun.awt.AWTFinalizer.run(AWTFinalizer.java:40)
> "Image Animator 0" (TID:0x2869aab0, sys_thread_t:0x29507f00, state:MW)
> prio=3
> sun.awt.image.ImageDecoder.close(ImageDecoder.java:163)
Image Animator 0 is callig close and is waiting on the monitor.
> "main" (TID:0x2866f0b0, sys_thread_t:0x8124a00, state:MW) prio=5
> sun.awt.motif.X11Graphics.finalize(X11Graphics.java:109)
> java.lang.String.<init>(String.java)
> java.io.DataInputStream.readUTF(DataInputStream.java)
> java.io.DataInputStream.readUTF(DataInputStream.java)
And the main thread is calling finalize, which is weird.
> sun.awt.image.GifImageDecoder@2869AE78/286FB0E8: owner "Image Animator
> 0" (0x29507f00, 1 entry)
> sun.awt.motif.MToolkit@286900B0/286DDD28: <unowned>
> Waiting to be notified:
> "AWT-Motif" (0x294e4f00)
> java.lang.Class@28699CD0/286F5140: owner "AWT-EventQueue-0"
> (0x294a2f00, 1 entry)
> java.lang.Class@2869AE80/286FB070: owner "Image Animator 0"
> (0x29507f00, 1 entry)
> java.lang.Class@28699EB8/286F58C8: owner "main" (0x8124a00, 1 entry)
> sun.awt.AWTFinalizer@2869AFC8/286DE6B0: <unowned>
> Waiting to be notified:
> "AWT-Finalizer" (0x29528f00)
> <unknown key> (0x29452f00): <unowned>
> Waiting to be notified:
> "Async Garbage Collector" (0x29452f00)
Interesting. Why is readObject() calling the GC? You're not making any
explicity calls to the garbage collector, are you?
> Registered Monitor Dump:
> Thread queue lock: <unowned>
> Name and type hash table lock: <unowned>
> String intern lock: <unowned>
> JNI pinning lock: <unowned>
> JNI global reference lock: <unowned>
> BinClass lock: <unowned>
> Class loading lock: owner "AWT-EventQueue-0" (0x294a2f00, 1 entry)
> Waiting to enter:
> "main" (0x8124a00)
> "Image Animator 0" (0x29507f00)
Ahh, this is a clue. It turns out that there are races in the Java
imaging code (which is a complete mess), and you may have stumbled on
them. Sometimes moving the code around and/or adding sleeps in places
causes the races to go away. *ESPECIALLY* when dealing with object
serialization.
You aren't using any static class locks by chance are you?
ie;
class foo {
static synchronized void foo() {
// Do something in here.
}
Nate
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