permgen

Until Java 7 there was an area in JVM memory called PermGen , where JVM used to keep its classes. In Java 8 it was removed and replaced by area called Metaspace . What are the most important differences between PermGen and Metaspace? The only difference I know is that java.lang.OutOfMemoryError: PermGen space can no longer be thrown and the VM parameter MaxPermSize is ignored. Mattias Jiderhamn The main difference from a user perspective - which I think the previous answer does not stress enough - is that Metaspace by default auto increases its size (up to what the underlying OS provides),

I want to get a dump of the PermGen to see why it is filling. Is there a way to analyze this? I already know about the common suspects like log4j, tomcat webapp reloading etc, but I have some custom proxy generation code in my application, too, and just want to look under the hood. Is this possible somehow? Puneet The PermGen normally consists of the string literal pool and loaded classes. To answer part of your problem, i.e. the string literal pool I wrote a utility to print a running JVM's string literal pool. It is available here: https://github.com/puneetlakhina/javautils/blob/master/src

I know what PermGen is, what it's used for, why it fails, how to increase it etc. What I don't know is what PermGen actually stands for. Permanent... Gen... something? Does anyone know what PermGen actually stands for? Tom Hawtin - tackline Permanent Generation. Details are of course implementation specific. Briefly, it contains the Java objects associated with classes and interned strings. In Sun's client implementation with sharing on, classes.jsa is memory mapped to form the initial data, with about half read-only and half copy-on-write. Java objects that are merely old are kept in the

It is mentioned at multiple posts: improper use of ThreadLocal causes Memory Leak. I am struggling to understand how Memory Leak would happen using ThreadLocal . The only scenario I have figured out it as below: A web-server maintains a pool of Threads (e.g. for servlets). Those threads can create memory leak if the variables in ThreadLocal are not removed because Threads do not die. This scenario does not mention "Perm Space" memory leak. Is that the only (major) use case of memory leak? PermGen exhaustions in combination with ThreadLocal are often caused by classloader leaks . An example:

I am working in Windows Environment. And I am getting this error everytime as I am working with tomcat- Apr 30, 2012 5:30:37 PM org.apache.catalina.core.StandardWrapperValve invoke SEVERE: Servlet.service() for servlet default threw exception java.lang.OutOfMemoryError: PermGen space 2012-04-30 17:30:37.719 INFO net.spy.memcached.MemcachedConnection: Connection state changed for sun.nio.ch.SelectionKeyImpl@4ae53a99 2012-04-30 17:30:37.719 INFO net.spy.memcached.MemcachedConnection: Reconnecting due to failure to connect to {QA sa=localhost/127.0.0.1:11211, #Rops=0, #Wops=0, #iq=0, topRop=null,