code: public synchronized TreeEntry<K, V> ceilingEntry(final K key) {
  		// Retorna la clave mas cercana mayor o igual a la clave indicada
  		return getRoundEntry(key, true, true);
  	}
docs: Returns the least key greater than or equal to the given key, or null if there is no such key.
  
  @param key the key
  @return the Entry with least key greater than or equal to key, or null if there is no such key