code: @Override
  	public void updateProperties( Dictionary<?,?> properties ) {
  
  		// Ignore iPojo properties
  		final List<String> propertiesToSkip = Arrays.asList(
  				"component",
  				"felix.fileinstall.filename" );
  
  		Map<String,String> map = new HashMap<> ();
  		for( Enumeration<?> en = properties.keys(); en.hasMoreElements(); ) {
  
  			Object key = en.nextElement();
  			String keyAsString = String.valueOf( key );
  			if( propertiesToSkip.contains( keyAsString ))
  				continue;
  
  			// "null" are not acceptable values in dictionaries
  			// (OSGi often use Hash tables)
  			Object value = properties.get( key );
  			map.put( keyAsString, String.valueOf( value ));
  		}
  
  		this.cache.clear();
  		this.cache.putAll( map );
  		this.logger.fine( "Preferences were updated in bulk mode." );
  	}
docs: Invoked by iPojo when one or several properties were updated from Config Admin.
  @param properties