如何清除permgen内存空间 [英] How to clear permgen memory space

问题描述

我正在使用MAT分析内存.

I am using MAT to analyze memory.

Size: 14.4 MB Classes: 7k Objects: 350.9k Class Loader: 116

我已经使用MAT内存分析仪获得了以上报告.但是我找不到清除这些类，对象的任何方法.
有什么方法可以删除所有这些对象并清理permgen内存.
我们可以清理permgen内存还是我必须增加eclipse.ini文件中的xms, xmx and launcher.XXMaxPermSize大小，并确保使用后所有对象都为空.

I've got the above report using MAT memory analyzer. But I can't find any way to clear those classes, objects.
Is there any way to remove all those object and clean permgen memory.
Can we clean permgen memory or I have to increase xms, xmx and launcher.XXMaxPermSize size in eclipse.ini file and make sure all object are nullify after use.

推荐答案

据我所知，没有清除permgen的功能.默认情况下，jvm无限期保留所有已加载的类.但是您可以使用-XX:+CMSClassUnloadingEnabled和-XX:+UseConcMarkSweepGC参数更改此行为.

As far as I know there is no function that clears permgen. On default, jvm holds all the loaded classes indefinitely. But you can change this behaviour using -XX:+CMSClassUnloadingEnabled and -XX:+UseConcMarkSweepGC parameters.

如果使用CMSClassUnloadingEnabled参数，GC还将清除PermGen并删除不再使用的类.

If you use CMSClassUnloadingEnabled parameter the GC will also sweep PermGen and remove classes which are no longer used.

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