Inferencing problem with generics

//@Typed
class RemoteMessageChannel<M extends Serializable> {// extends MessageChannel<M> {

//	static class MyMap<K,V> extends HashMap<K,WeakReference<V>> {
	
	static class MyMap extends HashMap<String,WeakReference<Class>> {	
//		V putIfNotYet(K key, V value) {
			
	
//		}
	}
	MyMap cache;
	
	void receiveBytes(String name) {
		ClassLoader parent
		if (name == this.class.name)
			this.class
		else { 
			def res = cache.get(name)?.get()
			if (res == this.class)
				throw new ClassNotFoundException()
			if (!res) {
				try {
					res = parent.loadClass(name)
				}
				catch (ClassNotFoundException e) {
					cache.putIfNotYet(name, this.class)
					throw e
				}
				cache.putIfNotYet(name, res)
			}
//			return res
		}
	}
	
}