[英]Tomcat8 memory leak
当我尝试在Java 8上停止tomcat8时,我收到一些内存泄漏错误:
org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [ROOT] 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:142)
com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:40)
23-Jan-2015 08:18:10.202 WARNING [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.clearReferencesThreads The web application [ROOT] appears to have started a thread named [pool-5-thread-1] but has failed to stop it. This is very likely to create a memory leak. Stack trace of thread
23-Jan-2015 08:18:10.205 SEVERE [localhost-startStop-2] org.apache.catalina.loader.WebappClassLoaderBase.checkThreadLocalMapForLeaks The web application [ROOT] created a ThreadLocal with key of type [com.util.ThreadLocalProperties$1] (value [com.util.ThreadLocalProperties$1@2fafda6e]) and a value of type [java.util.Properties] (value [{}]) but failed to remove it when the web application was stopped. Threads are going to be renewed over time to try and avoid a probable memory leak.
ThreadLocalProperties类是:
public class ThreadLocalProperties extends Properties {
private static final long serialVersionUID = -4260632266508618756L;
private final ThreadLocal<Properties> localProperties = new ThreadLocal<Properties>() {
@Override
protected Properties initialValue() {
return new Properties();
}
};
public ThreadLocalProperties(Properties properties) {
super(properties);
}
@Override
public String getProperty(String key) {
String localValue = localProperties.get().getProperty(key);
return localValue == null ? super.getProperty(key) : localValue;
}
@Override
public Object setProperty(String key, String value) {
return localProperties.get().setProperty(key, value);
}
public ThreadLocal<Properties> getThreadLocal() {
return localProperties;
}
}
我这样开始和停止它:
@WebListener()
public class GeneralListener implements ServletContextListener {
ThreadLocalProperties threadLocalProperties = new ThreadLocalProperties(System.getProperties());
@Override
public void contextDestroyed(ServletContextEvent arg0) {
threadLocalProperties.getThreadLocal().remove();
}
@Override
public void contextInitialized(ServletContextEvent arg0) {
System.setProperties(threadLocalProperties);
}
}
为什么我会得到所有这些内存泄漏错误? 同样,当我运行shutdown时,它不会关闭它,我必须手动终止进程。
怎么了?
没有什么可担心的。 这是一个标准消息tomcat输出,当它检测到应用程序已启动它自己的Thread
或创建一个ThreadLocal
。 如果在关闭时终止线程并在不再需要时删除threadlocals ,那么就没有问题了。
为什么我会得到所有这些内存泄漏错误? 同样,当我运行shutdown时,它不会关闭它,我必须手动终止进程。
我已经看到这种行为,当一个应用程序启动了ScheduledExecutor
(但这将发生在任何其他Thread
/ TheadPool
)并且没有在contextDestroyed
上关闭它。 因此,请检查您是否在应用程序/服务器停止时关闭了线程。
现在就你的具体问题服务器没有停止的原因:JDBC驱动程序在JVM中作为单例注册,并与所有webapp共享。 更多信息在这里。 解决问题的最佳方法是在Tomcat的/lib
文件夹中移动MySQL驱动程序。 如果你不能这样做,你可以尝试这个,但它更像是一个黑客,而不是一个真正的解决方案。
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