docs: public void put(Object locator, Object component) {
  		if (locator == null)
  			throw new NullPointerException("Locator cannot be null");
  		if (component == null)
  			throw new NullPointerException("Reference cannot be null");
  
  		synchronized (_lock) {
  			// Add reference to the set
  			_references.add(new Reference(locator, component));
  		}
  	}