Dear all. Hi, I'm developer of java application, and I have a question about logback. Our application uses logback and it stopped processing several times during the log output. But this problem is not reproducible and difficult to solve, so please help us. This is the part of jstack I got when the problem occurred. --------------------------------------- "main" #1 prio=5 os_prio=0 tid=0x0000000001d33800 nid=0x2320 waiting on condition [0x0000000001d2e000] java.lang.Thread.State: WAITING (parking) at sun.misc.Unsafe.park(Native Method) - parking to wait for <0x00000000f9498208> (a java.util.concurrent.locks.ReentrantLock$NonfairSync) at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175) at java.util.concurrent.locks.AbstractQueuedSynchronizer.parkAndCheckInterrupt(AbstractQueuedSynchronizer.java:836) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquireQueued(AbstractQueuedSynchronizer.java:870) at java.util.concurrent.locks.AbstractQueuedSynchronizer.acquire(AbstractQueuedSynchronizer.java:1199) at java.util.concurrent.locks.ReentrantLock$NonfairSync.lock(ReentrantLock.java:209) at java.util.concurrent.locks.ReentrantLock.lock(ReentrantLock.java:285) at java.util.concurrent.ArrayBlockingQueue.remainingCapacity(ArrayBlockingQueue.java:468) at ch.qos.logback.core.AsyncAppenderBase.isQueueBelowDiscardingThreshold(AsyncAppenderBase.java:134) at ch.qos.logback.core.AsyncAppenderBase.append(AsyncAppenderBase.java:126) at ch.qos.logback.core.UnsynchronizedAppenderBase.doAppend(UnsynchronizedAppenderBase.java:88) at ch.qos.logback.core.spi.AppenderAttachableImpl.appendLoopOnAppenders(AppenderAttachableImpl.java:48) at ch.qos.logback.classic.Logger.appendLoopOnAppenders(Logger.java:273) at ch.qos.logback.classic.Logger.callAppenders(Logger.java:260) at ch.qos.logback.classic.Logger.buildLoggingEventAndAppend(Logger.java:442) at ch.qos.logback.classic.Logger.filterAndLog_0_Or3Plus(Logger.java:396) at ch.qos.logback.classic.Logger.debug(Logger.java:523) --------------------------------------- Is this a bug? Or if this is not a bug, could you please tell me what was happening internally? =================================== [version information of our application] logback-core: 1.1.0 logback-classic:1.1.0 java8 =================================== Best regards