Grails PermGem error

Question

I need help with this problem. I need someone to explain to me why is this happening and how to prevent or avoid it.

Exception in thread "Thread-747" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-748" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-759" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-760" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-764" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-765" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-766" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-767" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-773" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-774" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-780" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-781" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-788" java.lang.OutOfMemoryError: PermGen space
Exception in thread "Thread-789" java.lang.OutOfMemoryError: PermGen space
2011-06-20 14:42:10,668 [http-8080-6] ERROR [/CM].[grails]  - Servlet.service() for servlet grails threw exception
java.lang.OutOfMemoryError: PermGen space
2011-06-20 14:42:10,668 [http-8080-6] ERROR [/CM].[default]  - Servlet.service() for servlet default threw exception
java.lang.OutOfMemoryError: PermGen space
: java.lang.OutOfMemoryError: PermGen space
        at org.apache.tools.ant.dispatch.DispatchUtils.execute(DispatchUtils.java:116)
        at _GrailsPackage_groovy$_run_closure8.doCall(_GrailsPackage_groovy:275)
        at _GrailsPackage_groovy$_run_closure8.call(_GrailsPackage_groovy)
        at _GrailsRun_groovy$_run_closure8.doCall(_GrailsRun_groovy:245)
        at RunApp$_run_closure1.doCall(RunApp.groovy:35)
        at gant.Gant$_dispatch_closure5.doCall(Gant.groovy:381)
        at gant.Gant$_dispatch_closure7.doCall(Gant.groovy:415)
        at gant.Gant$_dispatch_closure7.doCall(Gant.groovy)
        at gant.Gant.withBuildListeners(Gant.groovy:427)
        at gant.Gant.this$2$withBuildListeners(Gant.groovy)
        at gant.Gant$this$2$withBuildListeners.callCurrent(Unknown Source)
        at gant.Gant.dispatch(Gant.groovy:415)
        at gant.Gant.this$2$dispatch(Gant.groovy)
        at gant.Gant.invokeMethod(Gant.groovy)
        at gant.Gant.executeTargets(Gant.groovy:590)
        at gant.Gant.executeTargets(Gant.groovy:589)
Caused by: java.lang.OutOfMemoryError: PermGen space
--- Nested Exception ---
java.lang.OutOfMemoryError: PermGen space
Error automatically restarting container: java.lang.OutOfMemoryError: PermGen space
Error executing script RunApp: PermGen space
java.lang.OutOfMemoryError: PermGen space
Error executing script RunApp: PermGen space
Application context shutting down...
Application context shutdown.

Answer 1

The PermGen is a region of your JVM's memory that is used to load classes.

As you application executes, it uses more and more of this memory, especially if you are in a debugging environment, of if you make extensive use of closures.

The way to fix this is to add more of it!

This is done by passing one or two parameters to the JVM when launching your application.

The parameters are :

-XX:MaxPermSize=256m
-XX:PermSize=128m

(adjust the values to your specific needs)

The PermSize will be the initial size of the PermGen, and the MaxPermSize will be the maximum size at which it will increase before throwing you an exception like in your post.

By default, it is set to 64M, which is not much if you have a 'real' application.

PAY ATTENTION : Your total memory usage will be:Heap size + Perm Size