[jira] [Closed] (GROOVY-8035) Class unloading (PermGen) memory leak with Groovy Shell

["Paul King (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/GROOVY-8035?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Paul King closed GROOVY-8035.
-----------------------------

> Class unloading (PermGen) memory leak with Groovy Shell
> -------------------------------------------------------
>
>                 Key: GROOVY-8035
>                 URL: https://issues.apache.org/jira/browse/GROOVY-8035
>             Project: Groovy
>          Issue Type: Bug
>    Affects Versions: 2.4.7
>         Environment: Oracle JDK6, Oracle JDK7
>            Reporter: Gernot R. Bauer
>            Assignee: John Wagenleitner
>             Fix For: 2.4.8
>
>
> The following code causes a memory leak in perm gen reproducibly on Oracle JDK6 and 7.
> {code:java}
> import groovy.lang.GroovyShell;
> public class Demo {
>     public static void main(String[] args) throws Exception {
>         for (int i = 0; i < 10000000; i++) {
>             GroovyShell gs = new GroovyShell();
>             Script script = gs.parse(" 'Hello, World';");
>             Object result = script.run();
>             assert result.equals("Hello, World");
>         }
>     }
> }
> {code}
> Tested with the following VM options (with PermGen size 20MB), the execution results in java.lang.OutOfMemoryError: PermGen space after a little more than 2000 iterations.
> {noformat}
> -verbose:class -XX:+UnlockDiagnosticVMOptions -XX:+UnlockExperimentalVMOptions -XX:+CMSClassUnloadingEnabled -XX:+ExplicitGCInvokesConcurrentAndUnloadsClasses -XX:+TraceClassUnloading -XX:MaxPermSize=16M -XX:+UseConcMarkSweepGC -XX:+ExplicitGCInvokesConcurrent -XX:+PrintGCDetails -XX:-UseParNewGC
> {noformat}
> As a workaround, calling the following method with script.getClass() from above (as described in http://stackoverflow.com/a/41473210/2156613) seems to avoid this leak and trigger class unloading correctly:
> {code:java}
>     public static void clearAllClassInfo(Class<?> type) {
>         try {
>             Field globalClassValue = ClassInfo.class.getDeclaredField("globalClassValue");
>             globalClassValue.setAccessible(true);
>             GroovyClassValue classValueBean = (GroovyClassValue) globalClassValue.get(null);
>             classValueBean.remove(type);
>         } catch (Exception ex) {
>             throw new RuntimeException(ex);
>         }
>     }
> {code}
> This should be handled by Groovy itself, or (if this is not possible) there should be at least a possibility to trigger this functionality via a Groovy API call instead of having to create the above method in all applications using Groovy.



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