java.lang.OutOfMemoryError: PermGen space When Running Maven on IntelliJ

NOTE

This is not a Groovy related problem, but I’m using it to illustrate my problem and solution here.

PROBLEM

I recently tried mixing some Groovy code into my existing JEE project. I created a simple POGO that looks as sophisticated as this:-

class GroovyStuff {
	String name
}

Then, I configured one of my controllers to invoke that POGO:-

@Controller
@RequestMapping(value = "/")
public class HomeController {

    @RequestMapping(method = RequestMethod.GET)
    public String main() {
        GroovyStuff stuff = new GroovyStuff();
        stuff.setName("Hello Groovy");
        System.out.println(stuff.getName());
        return "home";
    }
}

After starting up Jetty, I hit that controller from the web and I get this infamous exception:-

java.lang.OutOfMemoryError: PermGen space
    at java.lang.ClassLoader.findBootstrapClass(Native Method)
    at java.lang.ClassLoader.findBootstrapClassOrNull(ClassLoader.java:926)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:297)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:239)
    at org.codehaus.plexus.classworlds.realm.ClassRealm.loadClass(ClassRealm.java:230)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:407)
    at org.eclipse.jetty.webapp.WebAppClassLoader.loadClass(WebAppClassLoader.java:383)
    at java.lang.Class.getDeclaredMethods0(Native Method)
    at java.lang.Class.privateGetDeclaredMethods(Class.java:2475)
    at java.lang.Class.getDeclaredMethods(Class.java:1818)
    at org.codehaus.groovy.reflection.CachedClass$3$1.run(CachedClass.java:84)
    at java.security.AccessController.doPrivileged(Native Method)
    at org.codehaus.groovy.reflection.CachedClass$3.initValue(CachedClass.java:81)
    at org.codehaus.groovy.reflection.CachedClass$3.initValue(CachedClass.java:79)
    at org.codehaus.groovy.util.LazyReference.getLocked(LazyReference.java:46)
    at org.codehaus.groovy.util.LazyReference.get(LazyReference.java:33)
    at org.codehaus.groovy.reflection.CachedClass.getMethods(CachedClass.java:250)
    at org.codehaus.groovy.runtime.m12n.SimpleExtensionModule.createMetaMethods(SimpleExtensionModule.java:111)
    at org.codehaus.groovy.runtime.m12n.SimpleExtensionModule.getMetaMethods(SimpleExtensionModule.java:93)
    at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.registerExtensionModuleFromProperties(MetaClassRegistryImpl.java:192)
    at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.registerExtensionModuleFromMetaInf(MetaClassRegistryImpl.java:174)
    at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.registerClasspathModules(MetaClassRegistryImpl.java:156)
    at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.<init>(MetaClassRegistryImpl.java:111)
    at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.<init>(MetaClassRegistryImpl.java:73)
    at groovy.lang.GroovySystem.<clinit>(GroovySystem.java:33)
    at org.codehaus.groovy.reflection.ClassInfo.getMetaClassUnderLock(ClassInfo.java:162)
    at org.codehaus.groovy.reflection.ClassInfo.getMetaClass(ClassInfo.java:192)
    at myproject.bean.GroovyStuff.$getStaticMetaClass(Stuff.groovy)
    at myproject.bean.GroovyStuff.<init>(Stuff.groovy)
    at myproject.controller.HomeController.main(HomeController.java:14)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)

I tried both GMaven Plugin and Groovy-Eclipse Compiler Plugin, and both gave me the same problem.

I checked my MAVEN_OPTS variable, and I have set a rather big max perm size, but it doesn’t fix the problem.

export MAVEN_OPTS="-Xms2048m -Xmx2048m -XX:PermSize=256m -XX:MaxPermSize=512m"

Then, I rebooted my laptop since that’s what most tech supports in the world would tell me to do when they encounter a problem… but it doesn’t fix the problem.

When I commented out the Groovy calls from the controller, everything works fine:-

@Controller
@RequestMapping(value = "/")
public class HomeController {

    @RequestMapping(method = RequestMethod.GET)
    public String main() {
        //GroovyStuff stuff = new GroovyStuff();
        //stuff.setName("Hello Groovy");
        //System.out.println(stuff.getName());
        return "home";
    }
}

After venting my frustration at the ping pong table and cursing at the laptop for many hours both at work and at home, I decided to run Jetty directly from the command line:-

mvn clean jetty:run

I was rather surprised that I no longer see the error.

SOLUTION

After poking around, I realized that IntelliJ doesn’t seem to honor my MAVEN_OPTS setting. When I run jetty:run goal from IntelliJ, I see the following output in the console:-

/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/java 
-Dmaven.home=/usr/local/apache-maven-3.0.3 -Dclassworlds.conf=/usr/local/apache-maven-3.0.3/bin/m2.conf 
-Didea.launcher.port=7533 "-Didea.launcher.bin.path=/Applications/IntelliJ IDEA 12.app/bin" 
-Dfile.encoding=UTF-8 -classpath "/usr/local/apache-maven-3.0.3/boot/plexus-classworlds-2.4.jar:/Applications/IntelliJ IDEA 12.app/lib/idea_rt.jar" 
com.intellij.rt.execution.application.AppMain org.codehaus.classworlds.Launcher --fail-fast --strict-checksums 
org.mortbay.jetty:jetty-maven-plugin:8.1.8.v20121106:run

So, I went to IntelliJ’s Preferences... -> Maven -> Runner and set my MAVEN_OPTS values under VM Options:-

IntelliJ's Maven VM Options

When I run jetty:run goal from IntelliJ again, now I see the following output in the console:-

/System/Library/Java/JavaVirtualMachines/1.6.0.jdk/Contents/Home/bin/java 
-Xms2048m -Xmx2048m -XX:PermSize=256m -XX:MaxPermSize=512m 
-Dmaven.home=/usr/local/apache-maven-3.0.3 -Dclassworlds.conf=/usr/local/apache-maven-3.0.3/bin/m2.conf 
-Didea.launcher.port=7534 "-Didea.launcher.bin.path=/Applications/IntelliJ IDEA 12.app/bin" 
-Dfile.encoding=UTF-8 -classpath "/usr/local/apache-maven-3.0.3/boot/plexus-classworlds-2.4.jar:/Applications/IntelliJ IDEA 12.app/lib/idea_rt.jar" 
com.intellij.rt.execution.application.AppMain org.codehaus.classworlds.Launcher --fail-fast --strict-checksums 
org.mortbay.jetty:jetty-maven-plugin:8.1.8.v20121106:run

Now, when I hit my controller again, the error went away.

The moral of the story is… if you still cannot fix your coding problem after spending many hours, go play ping pong.

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