public void clearCache() {
        // The iterator over the values collection is thread-safe.
        synchronized (classToCacheMap) {
            for (AssetCache cache : classToCacheMap.values()) {
                cache.clearCache();
            }
        }
    }
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