求高手解答下

Question

ERROR [ContainerBackgroundProcessor[StandardEngine[Catalina]]] ClickstreamListener.sessionDestroyed(60) | null
java.lang.NullPointerException
at com.opensymphony.clickstream.ClickstreamListener.sessionDestroyed(ClickstreamListener.java:55)
at org.apache.catalina.session.StandardSession.expire(StandardSession.java:702)
at org.apache.catalina.session.StandardSession.isValid(StandardSession.java:592)
at org.apache.catalina.session.ManagerBase.processExpires(ManagerBase.java:682)
at org.apache.catalina.session.ManagerBase.backgroundProcess(ManagerBase.java:667)
at org.apache.catalina.core.ContainerBase.backgroundProcess(ContainerBase.java:1316)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1601)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.processChildren(ContainerBase.java:1610)
at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1590)
at java.lang.Thread.run(Thread.java:619)以上错误开启tomcat之后不定时出现，最近出现的情况越来越频繁，但是不耽误项目运行 求高手帮解答~~~

Answer 1

Tomcat启动参数CATALINA_OPTS='-Xms512m -Xmx4096m -XX:PermSize=64M -XX:MaxNewSize=128m -XX:MaxPermSize=64m -XX:ParallelGCThreads=8 -XX:+UseConcMarkSweepGC调大点，例如256M,试试看。

Answer 2

应该是监听器销毁session的时候session并没有加载

Answer 3

HttpSessionEvent event = new HttpSessionEvent(getSession());可能是event为null，监听器销毁时，根据event获取session出错了吧