public synchronized V get(K key) {
        return this.map.get(key);
    }
Retrieves an entry from the cache.<br>
The retrieved entry becomes the MRU (most recently used) entry.

@param key
           the key whose associated value is to be returned.
@return the value associated to this key, or null if no value with this
        key exists in the cache.
jme3-terrain/src/main/java/com/jme3/terrain/geomipmap/LRUCache.java