Hello Zoltan, Looking at this exception and related code in AppenderAttachableImpl, moving the r.lock(); statement outside of the try block will not change anything because I believe that r.lock() does not throw exceptions. However, looking at ReentrantReadWriteLock.ReadLock class' lock() method, one is directed to the ReentrantReadWriteLock.Sync class and its acquireShared() method. If this method fails to acquire the lock due to a RuntimeException, then the subsequent r.unlock() call will fail with an IllegalMonitorStateException. In any case, r.lock() will not throw an exception since the exception is absorbed by the sync.acquireShared method. It would be quite helpful if you were able to reproduce the problem. We could place the r.unlock() invocation within a try/catch block (absorbing the IllegalMonitorStateException you got). However, this is may only obfuscate the real cause of the problem, that is an OutOfMemoryException or such. We could also imagine that there is a bug in ReentrantReadWriteLock. Given its complexity, it's not such an outlandish hypothesis. Otherwise, the only remaining possibility is a bug in logback. But we all know that is impossible. More seriously, I think this bug will be hard to nail down. Szel, Zoltan (IDEAS) wrote:
Hi,
We have hit the exception mentioned in the subject in one of our applications. We are using JDK 6 and Logback 0.9.14. Here is the stacktrace:
Caused by: java.lang.IllegalMonitorStateException at java.util.concurrent.locks.ReentrantReadWriteLock$Sync.tryReleaseShared(ReentrantReadWriteLock.java:363) at java.util.concurrent.locks.AbstractQueuedSynchronizer.releaseShared(AbstractQueuedSynchronizer.java:1253) at java.util.concurrent.locks.ReentrantReadWriteLock$ReadLock.unlock(ReentrantReadWriteLock.java:745) at ch.qos.logback.core.spi.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:64) at ch.qos.logback.classic.Logger.appendLoopOnAppenders(Logger.java:270) at ch.qos.logback.classic.Logger.callAppenders(Logger.java:257) at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:439) at ch.qos.logback.classic.Logger.filterAndLog_1(Logger.java:411) at ch.qos.logback.classic.Logger.debug(Logger.java:504)
I have checked the code and it seems to me this can only happen if the readLock.lock() method throws an exception:
*public* *int* appendLoopOnAppenders(E e) {
56 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#56> *int* size = 0;
57 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#57> *try* {
58 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#58> r.lock();
59 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#59> *for* (Appender<E> appender : appenderList) {
60 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#60> appender.doAppend(e);
61 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#61> size++;
62 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#62> }
63 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#63> } *finally* {
64 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#64> r.unlock();
65 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#65> }
66 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#66> *return* size;
67 <http://logback.qos.ch/xref/ch/qos/logback/core/spi/AppenderAttachableImpl.html#67> }
if r.lock() in line 58 throws an exception for some reason than in the finally block the unlock will throw also an exception which will hide the original one. I cannot see any other reason why the unlock would throw this exception in this scenario. I am not yet able to reproduce it, but I thought this exception worth a mail. The only suggestion I have for now is to move the r.lock() call out of the try block, because if that is the bad guy, than we would have the original exception propagated.
If I have more information on this issue I will update this thread.
Regards,
Zoltan Szel *Morgan Stanley | IDEAS PRACTICE AREAS *Lechner Odon fasor 8 | Floor 07 Budapest, 1095 Phone: +36 1 881-3978 Zoli.Szel@MorganStanley.com <mailto:Zoli.Szel@MorganStanley.com>
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