Java™ How To Program (Early Objects), Tenth Edition

17.9 Lambda Event Handlers

In Section 12.11, you learned how to implement an event handler using an anonymous inner class. Some event-listener interfaces—such as ActionListener and ItemListener—are functional interfaces. For such interfaces, you can implement event handlers with lambdas. For example, the following statement from Fig. 12.21:

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imagesJComboBox.addItemListener(   new ItemListener() // anonymous inner class   {      // handle JComboBox event      @Override      public void itemStateChanged(ItemEvent event)      {         // determine whether item selected         if (event.getStateChange() == ItemEvent.SELECTED)            label.setIcon(icons[               imagesJComboBox.getSelectedIndex()]);      } ...