public AssetLoader aquireLoader(AssetKey key) {
        // No need to synchronize() against map, its concurrent
        ImplThreadLocal local = extensionToLoaderMap.get(key.getExtension());
        if (local == null) {
            throw new AssetLoadException("No loader registered for type \""
                    + key.getExtension() + "\"");

        }
        return (AssetLoader) local.get();
    }
Returns the AssetLoader registered for the given extension
of the current thread.
@return AssetLoader registered with addLoader.
jme3-core/src/main/java/com/jme3/asset/ImplHandler.java