What does PermGen actually stand for?

java permgen
SCdF picture SCdF · Nov 25, 2008 · Viewed 166.4k times · Source

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?

Answer

Tom Hawtin - tackline picture Tom Hawtin - tackline · Nov 26, 2008

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 Tenured Generation.

Related questions

-XX:MaxPermSize with or without -XX:PermSize

We've run into a Java.lang.OutOfMemoryError: PermGen space error and looking at the tomcat JVM params, other than the -Xms and -Xmx params we also specify -XX:MaxPermSize=128m. After a bit of profiling I can see occasionally garbage …

Read More
"java.lang.OutOfMemoryError: PermGen space" in Maven build

I'm getting this error while building Maven project, I increased MAVEN_OPTS but all the same, I found some similar posts but they are refering to something else. How do I fix this? The system is out of resources. Consult …

Read More
How do I properly set the permgen size?

I have this VM with tomcat, java, and grails in it. I've been getting permgen errors so I looked around and found the solution: set JAVA_OPTS="-Xms256m -Xmx1024m -XX:PermSize=512m -XX:MaxPermSize=512m" I use SSH …

Read More