code: public static void setCurrentPreferenceKey(String key) {
  		LOCK.lock();
  		try {
  			currentPreferenceKey = (Strings.isNullOrEmpty(key)) ? DEFAULT_PREFERENCE_KEY : key;
  		} finally {
  			LOCK.unlock();
  		}
  	}
docs: Change the key used for storing the SARL runtime configuration
  into the preferences.
  
  <p>If the given key is <code>null</code> or empty, the preference key
  is reset to the {@link #DEFAULT_PREFERENCE_KEY}.
  
  @param key the new key or <code>null</code>.