ContainerListener (Java SE 26 & JDK 26)
Description: declaration: module: java.desktop, package: java.awt.event, interface: ContainerListener
Keywords: java.awt.event.ContainerListener interface

# Interface ContainerListener

All Superinterfaces:
  `EventListener`

All Known Implementing Classes:
  `AWTEventMulticaster, BasicToolBarUI.ToolBarContListener, Container.AccessibleAWTContainer.AccessibleContainerHandler, ContainerAdapter, JComponent.AccessibleJComponent.AccessibleContainerHandler, MetalToolBarUI.MetalContainerListener`

public interface ContainerListener extends EventListener
The listener interface for receiving container events. The class that is interested in processing a container event either implements this interface (and all the methods it contains) or extends the abstract `ContainerAdapter` class (overriding only the methods of interest). The listener object created from that class is then registered with a component using the component's `addContainerListener` method. When the container's contents change because a component has been added or removed, the relevant method in the listener object is invoked, and the `ContainerEvent` is passed to it.

Container events are provided for notification purposes ONLY; The AWT will automatically handle add and remove operations internally so the program works properly regardless of whether the program registers a `ContainerListener` or not.

Since:
  1.1
See Also:
  - `ContainerAdapter`
  - `ContainerEvent`
  - Tutorial: Writing a Container Listener

- ## Method Summary

  Modifier and Type
  Method
  Description
  `void`
  `componentAdded(ContainerEvent e)`
  Invoked when a component has been added to the container.
  `void`
  `componentRemoved(ContainerEvent e)`
  Invoked when a component has been removed from the container.

- ## Method Details

  - ### componentAdded

    void componentAdded(ContainerEvent e)
    Invoked when a component has been added to the container.
    Parameters:
      `e` - the event to be processed

  - ### componentRemoved

    void componentRemoved(ContainerEvent e)
    Invoked when a component has been removed from the container.
    Parameters:
      `e` - the event to be processed