The current MetaClass and MetaClassRegistry do not integrate as cleanly in application server environments as they could.

In particular, groovy classes loaded by an application server classloader are stored in a static hashmap, which can prevent GC when the classloaders are dropped.

In addition, dynamically created classes are not loaded properly, but are attempted to be loaded in a global classloader context (which, of course does not work.)

The solutions are:
1) Make the MetaClassRegistry.metaClasses Map as WeakHashMap to allow dropped classes to be garbage collected.
2) Add a MetaClassRegistry.loaderMap to create GroovyClassLoaders on top of the context ClassLoader, instead of dropping to a global GroovyClassLoader.

Assuming this change is implemented, Resin can use groovy generated classes exactly as any other class. (Which would be very, very cool.)

— MetaClassRegistry.java.orig 2004-04-02 19:21:52.000000000 -0800
+++ MetaClassRegistry.java 2004-04-02 19:17:41.000000000 -0800
@@ -48,7 +48,7 @@
import java.beans.IntrospectionException;
import java.util.ArrayList;
import java.util.Collections;
-import java.util.HashMap;
+import java.util.WeakHashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
@@ -64,9 +64,10 @@

• @version $Revision: 1.10 $
  */
  public class MetaClassRegistry {

• private Map metaClasses = Collections.synchronizedMap(new HashMap());
  + private Map metaClasses = Collections.synchronizedMap(new WeakHashMap());
  private boolean useAccessible;
  private GroovyClassLoader loader = new GroovyClassLoader(getClass().getClassLoader());
  + private Map loaderMap = Collections.synchronizedMap(new WeakHashMap());

public MetaClassRegistry() {
this(true);
@@ -118,12 +119,33 @@
/**

• A helper class to load meta class bytecode into the class loader
  */

• public Class loadClass(String name, byte[] bytecode) throws ClassNotFoundException {
• return loader.loadClass(name, bytecode);
  + public Class loadClass(ClassLoader loader, String name, byte[] bytecode) throws ClassNotFoundException { + return getGroovyLoader(loader).loadClass(name, bytecode); }

• public Class loadClass(String name) throws ClassNotFoundException {
• return loader.loadClass(name);
  + public Class loadClass(ClassLoader loader, String name) throws ClassNotFoundException { + return getGroovyLoader(loader).loadClass(name); + }
  +
  + private GroovyClassLoader getGroovyLoader(ClassLoader loader)
  + {
  + if (loader instanceof GroovyClassLoader)
  + return (GroovyClassLoader) loader;
  +
  + synchronized (loaderMap)
  Unknown macro: {+ GroovyClassLoader groovyLoader;+ groovyLoader = (GroovyClassLoader) loaderMap.get(loader);+ if (groovyLoader == null) { + if (loader == null || loader == getClass().getClassLoader()) + groovyLoader = this.loader; + else + groovyLoader = new GroovyClassLoader(loader); + + loaderMap.put(loader, groovyLoader); + }++ return groovyLoader;+ }
  
  }

/**

— MetaClass.java.orig 2004-04-02 19:21:41.000000000 -0800
+++ MetaClass.java 2004-04-02 18:53:43.000000000 -0800
@@ -1448,7 +1448,7 @@
GroovyClassLoader gloader = (GroovyClassLoader) loader;
return gloader.loadClass(name, bytecode);
}

• return registry.loadClass(name, bytecode);
  + return registry.loadClass(loader, name, bytecode);
  }

protected Class loadReflectorClass(String name) throws ClassNotFoundException { @@ -1457,7 +1457,7 @@ GroovyClassLoader gloader = (GroovyClassLoader) loader; return gloader.loadClass(name); }

• return registry.loadClass(name);
  + return registry.loadClass(loader, name);
  }

public List getMethods() {