如果存在真正的内存泄漏，增加永久生成大小或调整GC参数将不起作用。如果您的应用程序或某些第三方库使用，泄漏类加载器，唯一真正和永久的解决方案是找到这个泄漏并修复它。有许多工具可以帮助您，最近的一个工具是Plumbr，它刚刚发布了一个具有所需功能的新版本。

人们常犯的错误是认为堆空间和永久空间是相同的，这是完全错误的。您可能在堆中有很多剩余空间，但仍然可能在permgen中耗尽内存。

Common causes of OutofMemory in PermGen is ClassLoader. Whenever a class is loaded into JVM, all its meta data, along with Classloader, is kept on PermGen area and they will be garbage collected when the Classloader which loaded them is ready for garbage collection. In Case Classloader has a memory leak than all classes loaded by it will remain in memory and cause permGen outofmemory once you repeat it a couple of times. The classical example is Java.lang.OutOfMemoryError:PermGen Space in Tomcat.

现在有两个方法来解决这个问题: 1. 检查内存泄漏的原因或是否存在内存泄漏。 2. 通过使用JVM参数-XX:MaxPermSize和-XX:PermSize来增加PermGen空间的大小。

你也可以在Java中查看Java.lang. outofmemoryerror的2 Solution来了解更多细节。

尝试-XX:MaxPermSize=256m，如果仍然存在，尝试-XX:MaxPermSize=512m

App server PermGen errors that happen after multiple deployments are most likely caused by references held by the container into your old apps' classloaders. For example, using a custom log level class will cause references to be held by the app server's classloader. You can detect these inter-classloader leaks by using modern (JDK6+) JVM analysis tools such as jmap and jhat to look at which classes continue to be held in your app, and redesigning or eliminating their use. Usual suspects are databases, loggers, and other base-framework-level libraries.

参见类加载器泄漏:可怕的“java.lang。OutOfMemoryError: PermGen space”异常，特别是它的后续帖子。

他们说Tomcat的最新版本(6.0.28或6.0.29)可以更好地处理重新部署servlet的任务。

从Tomcat的bin目录打开tomcat7w，或者在开始菜单中键入Monitor Tomcat (打开一个带有各种服务信息的选项卡窗口)。 在Java Options文本区域中添加这一行: - xx: MaxPermSize = 128 “初始内存池”设置为“1024”(可选)。 “最大内存池”设置为“1024”(可选)。 单击Ok。 重启Tomcat服务。