jvm full gc即使permgen已满也无法卸载类 [英] jvm full gc can't unload classes even permgen is full

问题描述

由于permgen已满，我们的生产服务器进行了OOM.使用 jmap -permstat 检查permgen区域，我们发现 com.sun.xml.ws.client.WSSServiceDelegatingLoader 加载了许多类.加载的类是 com.sun.proxy.$ ProxyXXX ，其中 XXX 是一个int序列.

Our production server went OOM because permgen is full. Using jmap -permstat to check the permgen area, we found there were many classes loaded by com.sun.xml.ws.client.WSSServiceDelegatingLoader. The loaded classes are com.sun.proxy.$ProxyXXX, where XXX is an int sequence.

这些类加载的堆栈跟踪如下:

the stacktrace for these classloading is as follow:

最终，JVM变成了OOM，完整的gc无法回收任何permgen内存.奇怪的是，如果我在VisualVM中单击系统GC"，则将卸载这些类，并且permgen的使用率将下降.

eventually, the JVM went OOM, full gc can't reclaim any permgen memory. What is strange is that if I click System GC in VisualVM, the classes are unloaded and the usage of permgen goes down.

我们的JDK版本是1.7.0.80，我们添加了 CMSClassUnloadingEnabled .

Our JDK version is 1.7.0.80， we have added CMSClassUnloadingEnabled.

-XX:+ExplicitGCInvokesConcurrent

-XX:+UseConcMarkSweepGC

-XX:CMSInitiatingOccupancyFraction=60

-XX:+UseParNewGC

-XX:+CMSParalledlRemarkEnabled

-XX:+UseCMSCompactAtFullCollection

-XX:+CMSFullGCsBeforeCompaction=0

-XX:+CMSCLassUnloadingEnabled

-XX:MaxTenuringThreshold=18

-XX:+UseCMSInitialtingOccupancyOnly

-XX:SurvivorRatio=4

-XX:ParallecGCThreads=16

我们的代码已经运行了很长时间了.最新操作是WebLogic修补程序.这真的让我感到困惑.有人可以帮我解决这个问题，非常感谢！

Our code has been running for a long time. The most recent operation is a WebLogic patch. This really confused me. Could someone give me some help with this issue, many thanks!

推荐答案

这是一个已知的错误例如，每次使用Weblogic Server 12.1.3中捆绑的库JAX-WS RI 2.2创建JAX-WS客户端时，

Every time a JAX-WS client is created, for instance, using library JAX-WS RI 2.2 which is bundled in Weblogic Server 12.1.3

com.sun.xml.ws.client.WSServiceDelegate$DelegatingLoader#1

客户端代理类正被加载到类加载器中:

Client proxy classes are being loaded into classloader:

([Loaded com.sun.proxy.$Proxy979 from com.sun.xml.ws.client.WSServiceDelegate$DelegatingLoader] )

解决方案/解决方法:解决此错误的位置，请替换JAX-WS客户端.

Solution/Workaround: Replace JAX-WS client where this bug is solved.

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