每次停止或重新启动 tomcat服务器NetBeans(Services > Servers)服务器长时间，并且还会给出“停止Tomcat失败。”错误消息。。有没有解决这个问题的方法？
16-Dec-2015 12:50:44.951 INFO [main] org.apache.catalina.core.StandardServer.await A valid shutdown command was received via the shutdown port. Stopping the Server instance.
16-Dec-2015 12:50:44.952 INFO [main] org.apache.coyote.AbstractProtocol.pause Pausing ProtocolHandler ["http-apr-8084"]
16-Dec-2015 12:50:45.003 INFO [main] org.apache.coyote.AbstractProtocol.pause Pausing ProtocolHandler ["ajp-apr-8009"]
16-Dec-2015 12:50:45.054 INFO [main] org.apache.catalina.core.StandardService.stopInternal Stopping service Catalina
16-Dec-2015 12:50:45.138 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesJdbc The web application [Imp] registered the JDBC driver [com.mysql.jdbc.Driver] but failed to unregister it when the web application was stopped. To prevent a memory leak, the JDBC Driver has been forcibly unregistered.
16-Dec-2015 12:50:45.139 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [Imp] appears to have started a thread named [MySQL Statement Cancellation Timer] 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.Object.wait(Object.java:502)
java.util.TimerThread.mainLoop(Timer.java:526)
java.util.TimerThread.run(Timer.java:505)
16-Dec-2015 12:50:45.139 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [Imp] appears to have started a thread named [pool-1-thread-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)
16-Dec-2015 12:50:45.166 INFO [main] org.apache.coyote.AbstractProtocol.stop Stopping ProtocolHandler ["http-apr-8084"]
16-Dec-2015 12:50:45.221 INFO [main] org.apache.coyote.AbstractProtocol.stop Stopping ProtocolHandler ["ajp-apr-8009"]
16-Dec-2015 12:50:45.271 INFO [main] org.apache.coyote.AbstractProtocol.destroy Destroying ProtocolHandler ["http-apr-8084"]
16-Dec-2015 12:50:45.272 INFO [main] org.apache.coyote.AbstractProtocol.destroy Destroying ProtocolHandler ["ajp-apr-8009"]