quartz集群报错but has failed to stop it. This is very likely to create a memory leak.

在一台配置1核2G内存的阿里云服务器上运行quartz；执行定时任务报如下异常，而在本地开发环境中则正常运行。

10-Sep-2016 11:43:50.415 WARNING [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [faxian] appears to have started a thread named [logback-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread: sun.misc.Unsafe.park(Native Method) java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215) java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078) java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093) java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809) java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1067) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1127) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617) java.lang.Thread.run(Thread.java:745)10-Sep-2016 11:43:50.415 WARNING [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [faxian] appears to have started a thread named [Abandoned connection cleanup thread] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread: java.lang.Object.wait(Native Method) java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143) com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:43)10-Sep-2016 11:43:50.416 WARNING [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [faxian] appears to have started a thread named [clusterQuartzScheduler_Worker-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread: java.lang.Object.wait(Native Method) org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:568)10-Sep-2016 11:43:50.417 WARNING [localhost-startStop-1] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [faxian] appears to have started a thread named [clusterQuartzScheduler_Worker-2] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread: java.lang.Object.wait(Native Method)

根据异常，初步判断是内存溢出导致的问题。查看服务器内存使用情况

[root@test-server logs]#  free -h              total       used       free     shared    buffers     cached Mem:          1.8G       1.7G       84M       9.4M       154M       520M -/+ buffers/cache:       1.1G       759M Swap:           0B         0B         0B

于是查看quartz的配置

pool-size="10"，queue-capacity="20"。

然而根据实际情况并，连接池数量和容量并不需要这么大。改成pool-size="1"，queue-capacity="1"，再次启动不再报错。

查看服务器内存使用情况

[root@test-server logs]#  free -h             total       used       free     shared    buffers     cachedMem:          1.8G       1.7G       141M       9.3M       154M       422M-/+ buffers/cache:       1.1G       718MSwap:           0B         0B         0B