Tomcat 6内存泄漏日志条目

Question

以下是我在CentOS机器上的Catalina.out文件中唯一条目的录入。我正在使用Spring 3和我的应用程序运行Tomcat
6。他们一整堆，所以我只是挑选了一些不断重复的东西。这并非一直发生，但至少每周发生一次。

问题是我该怎么做才能防止风箱发生？

Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesJdbc

SEVERE: The web application [] registered the JBDC 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.

Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads

SEVERE: The web application [] appears to have started a thread named [com.iteezy.shared.domain.DirEntry.data] but has failed to stop it. This is very likely to create a memory leak.


Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
SEVERE: The web application [] appears to have started a thread named

[com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0] but has failed to stop it. This is very likely to create a memory leak.


Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads

SEVERE: The web application [] appears to have started a thread named [File Reaper] but has failed to stop it. This is very likely to create a memory leak.

Feb 3, 2011 2:37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads

SEVERE: The web application [] appears to have started a thread named [pool-1-thread-22] but has failed to stop it. This is very likely to create a memory leak.

37:48 PM org.apache.catalina.loader.WebappClassLoader clearReferencesThreads
b application [] appears to have started a thread named

[org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-2] but has failed to stop it. This is very likely to create a memory leak.

37:48 PM org.apache.catalina.loader.WebappClassLoader clearThreadLocalMap

b application [] created a ThreadLocal with key of type [net.sf.json.AbstractJSON$1] (value [net.sf.json.AbstractJSON$1@40bbb3d6]) and a value of type [java.util.HashSet] (value [[]]) but failed to remove it when the web application was stopped. This is very likely to create a memory leak.

Answer 1

当您定义一个外部标志时，应该在设置 该volatile标志的同时轮询该线程并退出该线程。否则，该线程可能永远不会看到其他线程所做的更改。

但是，标准API中已经有类似的功能-
它称为interrupt()方法和Thread.currentThread().isInterrupted()。无需重复已经存在的逻辑。请参阅：停止特定的Java线程。

话虽这么说，调用interrupt()每个线程也是一个坏主意，因为不能保证所有线程都会对此做出响应。检查您的异常情况后，我发现以下线程未正确清理：

• com.mchange.v2.async.ThreadPoolAsynchronousRunner$PoolThread-#0-关闭C3P0数据源。由于您使用的是Spring，因此只需添加destroy-method="close"。我们已经完成了这个线程。

• File Reaper-据我所知，该线程是由FileCleaningTracker创建的。FileCleaningTracker.exitWhenFinished()关闭应用程序时（或者不再需要该类，我从没使用过）时，需要显式调用，或者让Spring进行此操作（请参见上文）。某些第三方库可能会使用它并且无法正确关闭-这意味着它存在错误。

• pool-1-thread-22-这是ExecutorsUtility内部创建的线程之一ExecutorService。确保shutdown()在关闭过程中调用应用程序中的每个此类池。

• org.springframework.scheduling.quartz.SchedulerFactoryBean#0_Worker-2-Quartz工作线程（实际运行作业的线程）。SchedulerFactoryBean自动为您关闭调度程序，我认为Tomcat错误在这里，我也经常看到此错误。不过貌似设置SchedulerFactoryBean.waitForJobsToCompleteOnShutdown来true解决这个问题。

• com.iteezy.shared.domain.DirEntry.data-我不确定这一点。它是您自己的线程需要在关闭时中断，还是H2数据库线程（？）需要检查其堆栈以猜测其来源。

底线是：不要仅仅杀死所有移动的内容（实际上，Tomcat在发出此警告之后会为您执行此操作），而是确定线程的来源，并使用特定close()于框架/库的方法来进行进一步清理。要温柔。