Hi,
It is a known problem that 4.0.4 and EJB-3 leaks Hibernate lazy proxy classes generated by Javassist. The cache introduced in Javassist-3.4 (4.0.4 ships with Javassist-3.2) should solve the problem, but unfortunately doesn't. Probably because Hibernate uses a different MethodHandler for each new proxy and so you get a cache miss.
However it is possible to use Javassist-3.4 and supply a custom ClassLoaderProvider instance. It is important that this provide creates a new CL instance that just delegates. So the CL can be collected (and so can the proxy). Here is how to do that. The code can be put into a service mbean:
ProxyFactory.useCache = false;
ProxyFactory.classLoaderProvider = new ClassLoaderProvider() {
public ClassLoader get(ProxyFactory pf) {
ClassLoader parent = getClassLoader(pf);
ClassLoader cl = new ClassLoader(parent) {
@Override
public Class loadClass(final String className) throws ClassNotFoundException {
try {
return super.loadClass(className);
} catch (ClassNotFoundException e) {
// only allow loading of ProxyObject from this loader
if (className.equals(ProxyObject.class.getName())) {
return ProxyObject.class.getClassLoader().loadClass(className);
}
// was some other classname, throw the CNFE
throw e;
}
}
};
return cl;
}
private ClassLoader getClassLoader(ProxyFactory pf) {
Class superClass = pf.getSuperclass();
Class[] interfaces = pf.getInterfaces();
ClassLoader loader = null;
if (superClass != null && !superClass.getName().equals("java.lang.Object"))
loader = superClass.getClassLoader();
else if (interfaces != null && interfaces.length > 0)
loader = interfaces[0].getClassLoader();
if (loader == null) {
loader = getClass().getClassLoader();
// In case javassist is in the endorsed dir
if (loader == null) {
loader = Thread.currentThread().getContextClassLoader();
if (loader == null)
loader = ClassLoader.getSystemClassLoader();
}
}
return loader;
}
};
I don't know if this leak is fixed in later JBoss versions.
