Tomcat8内存泄漏

Question

当我尝试在 Java 8 上停止 tomcat8 时，出现了一些内存泄漏错误：

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] (value [com.util.ThreadLocalProperties@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.

class ThreadLocalProperties 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);
    }
}

为什么我会收到所有这些内存泄漏错误？同样，当我运行关机时，它并没有关闭，我必须手动终止进程。

怎么了？

Answer 1

我认为你的问题类似于this。当您重新部署该应用程序时，apache 会在 system.gc(); 不起作用的地方以增量方式将其部署到自身，并且在开发阶段进行几次重新部署后，永久生成的 space 已满，您会收到内存泄漏错误。

请在几次重新部署后继续重新启动您的服务器，以便通过重新启动清除 PermGen space。

或

a 你也可以通过更改server.xml中的PermGen space来解决。请访问 here.

希望对您有所帮助。

Answer 2

没有什么可担心的。这是一个标准消息 tomcat 当它检测到应用程序已经启动它自己的 Thread 或创建一个 ThreadLocal 时输出。如果您在关闭时终止线程并在不再需要时删除 threadlocals，那么就不会有问题。

Why would I get all this memory leaks errors? as well, when I run shutdown, it doesn't shut it down, I have to manually kill the process.

我已经看到这种行为，当应用程序启动 ScheduledExecutor（但任何其他 Thread/TheadPool 时都会发生这种情况）并且没有关闭它contextDestroyed。因此，请检查您是否在 application/server 停止时关闭您的线程。

现在解决您的具体问题 为什么服务器不停止： JDBC 驱动程序在 JVM 中注册为单例，并与所有 Web 应用程序共享。更多信息 here. The best solution to your problem is to move the MySQL driver in Tomcat's /lib folder. If you cannot do that you can try this 但它更像是 hack 而不是真正的解决方案。

Tomcat8内存泄漏

Tomcat8 memory leak

java

tomcat

memory-leaks