JNI Question 2

Hello again,
I am seeing an intermittent error come up that's hanging my application. This is occurring when I make the following call into my cocoa library using Java JNI:
JNIEXPORT jint JNICALL JavaMacTaskTrayIconcreateTaskTrayIcon(JNIEnv* env, jobject caller, jstring iconFilePath)
NSStatusItem * statusItem = [[NSStatusBar systemStatusBar]
statusItemWithLength:NSVariableStatusItemLength];
Here's the error I see:
2006-07-18 10:02:49.821 java[6511] * Assertion failure in -[NSViewHierarchyLock unlockTopMostReader], AppKit.subproj/NSViewHierarchyLock.m:444
2006-07-18 10:02:49.822 java[6511] Apple AWT Startup Exception : Invalid parameter not satisfying: th
2006-07-18 10:02:49.822 java[6511] Apple AWT Restarting Native Event Thread
I've elminated all other code in my cocoa library and still get the problem, so I have isolated the problem to the one call listed above.
Since this error occurrs intermttently, I think that it's some kind of threading issue. When java calls into JNI, should I move the NSStatusItem creation call to some other privileged thread, or do I need to acquire some kind of lock before making the call?
Any input would be appreciated.
Many Thanks,
Patrick Arnesen
VivraTerra Software Corp.
Mac OS X (10.4.6)

Hi
A google search of this error indicates that it appears from time to time and can be quite difficult to tie down, however, it appears to have nothing to do with JNI.
On one forum I saw this comment in relation to this error:
"The most common cause is unmatched -[NSView unlockFocus] invocations."
http://www.cocoabuilder.com/archive/message/cocoa/2006/1/11/154180
If this can shed some light on your problem then great, otherwise I suggest you put the error message into google and see if the responses can help you.
Good luck
Bob

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}I already tried working with native HDCs (GetDC, CreateCompatibleBitmap, SelectObject, GetDIBits, ...) but this just complicates stuff and gives me the same result.

Have you verified what the "native DLL" gives you back on the second call?The HBITMAP handle returned is the same each call (no matter which thread). The actual BITMAP associated with this handle is only updated in the first thread.
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Try printing out the hash for each instance.I have written the image to a file in the native code itself to eliminate anything related to the mechanism of returning the BufferedImage. This had the same result.
The return values of all native calls all indicate successful calls.
I am suspecting the native side of creating a second graphical context for the second thread while it keeps refering to the first context.
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> With those functions that take JNI Version parameter, will the resulting JNIEnv only have those function table entries for that version, or the most recent one?
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> Does this actually mean they should use a va_list and the C calling convention, rather than JNICALL and explicit params (as in "ordinary" native methods)?
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-slj-

JNI related question

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