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## javax.swing
Class JApplet

    java.lang.Object
      java.awt.Component
          java.awt.Container
              java.awt.Panel
                  java.applet.Applet
                      javax.swing.JApplet

All Implemented Interfaces:
  Accessible, ImageObserver, MenuContainer, RootPaneContainer, Serializable

public class JApplet
extends Applet
implements Accessible, RootPaneContainer

An extended version of java.applet.Applet that adds support for the JFC/Swing component architecture. You can find task-oriented documentation about using `JApplet` in The Java Tutorial, in the section How to Make Applets.

The JApplet class is slightly incompatible with java.applet.Applet. JApplet contains a JRootPane as it's only child. The contentPane should be the parent of any children of the JApplet. This is different than java.applet.Applet, e.g. to add a child to an an java.applet.Applet you'd write:

           applet.add(child);

However using JApplet you need to add the child to the JApplet's contentPane instead:

           applet.getContentPane().add(child);

The same is true for setting LayoutManagers, removing components, listing children, etc. All these methods should normally be sent to the contentPane() instead of the JApplet itself. The contentPane() will always be non-null. Attempting to set it to null will cause the JApplet to throw an exception. The default contentPane() will have a BorderLayout manager set on it.

Please see the JRootPane documentation for a complete description of the contentPane, glassPane, and layeredPane properties.

For the keyboard keys used by this component in the standard Look and Feel (L&F) renditions, see the `JApplet` key assignments.

Warning: Serialized objects of this class will not be compatible with future Swing releases. The current serialization support is appropriate for short term storage or RMI between applications running the same version of Swing. As of 1.4, support for long term storage of all JavaBeansTM has been added to the `java.beans` package. Please see `XMLEncoder`.

Nested Class Summary
`protected class` | `JApplet.AccessibleJApplet` This class implements accessibility support for the `JApplet` class.

Nested classes inherited from class java.applet.Applet
`Applet.AccessibleApplet`

Nested classes inherited from class java.awt.Panel
`Panel.AccessibleAWTPanel`

Nested classes inherited from class java.awt.Container
`Container.AccessibleAWTContainer`

Nested classes inherited from class java.awt.Component
`Component.AccessibleAWTComponent, Component.BltBufferStrategy, Component.FlipBufferStrategy`

Field Summary
`protected AccessibleContext` | `accessibleContext`
`protected JRootPane` | `rootPane`
`protected boolean` | `rootPaneCheckingEnabled`

Fields inherited from class java.awt.Component
`BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT`

Fields inherited from interface java.awt.image.ImageObserver
`ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH`

Constructor Summary
`JApplet()` Creates a swing applet instance.

Method Summary
`protected void` | `addImpl(Component comp, Object constraints, int index)` By default, children may not be added directly to a this component, they must be added to its contentPane instead.
`protected JRootPane` | `createRootPane()` Called by the constructor methods to create the default rootPane.
`AccessibleContext` | `getAccessibleContext()` Gets the AccessibleContext associated with this JApplet.
`Container` | `getContentPane()` Returns the contentPane object for this applet.
`Component` | `getGlassPane()` Returns the glassPane object for this applet.
`JMenuBar` | `getJMenuBar()` Returns the menubar set on this applet.
`JLayeredPane` | `getLayeredPane()` Returns the layeredPane object for this applet.
`JRootPane` | `getRootPane()` Returns the rootPane object for this applet.
`protected boolean` | `isRootPaneCheckingEnabled()`
`protected String` | `paramString()` Returns a string representation of this JApplet.
`void` | `remove(Component comp)` Removes the specified component from this container.
`void` | `setContentPane(Container contentPane)` Sets the contentPane property.
`void` | `setGlassPane(Component glassPane)` Sets the glassPane property.
`void` | `setJMenuBar(JMenuBar menuBar)` Sets the menubar for this applet.
`void` | `setLayeredPane(JLayeredPane layeredPane)` Sets the layeredPane property.
`void` | `setLayout(LayoutManager manager)` By default the layout of this component may not be set, the layout of its contentPane should be set instead.
`protected void` | `setRootPane(JRootPane root)` Sets the rootPane property.
`protected void` | `setRootPaneCheckingEnabled(boolean enabled)` If true then calls to add() and setLayout() will cause an exception to be thrown.
`void` | `update(Graphics g)` Just calls `paint(g)`.

Methods inherited from class java.applet.Applet
`destroy, getAppletContext, getAppletInfo, getAudioClip, getAudioClip, getCodeBase, getDocumentBase, getImage, getImage, getLocale, getParameter, getParameterInfo, init, isActive, newAudioClip, play, play, resize, resize, setStub, showStatus, start, stop`

Methods inherited from class java.awt.Panel
`addNotify`

Methods inherited from class java.awt.Container
`add, add, add, add, add, addContainerListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getAlignmentX, getAlignmentY, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getInsets, getLayout, getListeners, getMaximumSize, getMinimumSize, getPreferredSize, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paint, paintComponents, preferredSize, print, printComponents, processContainerEvent, processEvent, remove, removeAll, removeContainerListener, removeNotify, setFocusCycleRoot, setFocusTraversalKeys, setFocusTraversalPolicy, setFont, transferFocusBackward, transferFocusDownCycle, validate, validateTree`

Methods inherited from class java.awt.Component
`action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, contains, createImage, createImage, createVolatileImage, createVolatileImage, disable, disableEvents, dispatchEvent, enable, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getFontMetrics, getForeground, getGraphics, getGraphicsConfiguration, getHeight, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocation, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMouseWheelListeners, getName, getParent, getPeer, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getSize, getToolkit, getTreeLock, getWidth, getX, getY, gotFocus, handleEvent, hasFocus, hide, imageUpdate, inside, isBackgroundSet, isCursorSet, isDisplayable, isDoubleBuffered, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isOpaque, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, printAll, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processKeyEvent, processMouseEvent, processMouseMotionEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, reshape, setBackground, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setEnabled, setFocusable, setFocusTraversalKeysEnabled, setForeground, setIgnoreRepaint, setLocale, setLocation, setLocation, setName, setSize, setSize, setVisible, show, show, size, toString, transferFocus, transferFocusUpCycle`

Methods inherited from class java.lang.Object
`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

Field Detail

### rootPane

    protected JRootPane rootPane

See Also:
  `getRootPane()`, `setRootPane(javax.swing.JRootPane)`

### rootPaneCheckingEnabled

    protected boolean rootPaneCheckingEnabled

See Also:
  `isRootPaneCheckingEnabled()`, `setRootPaneCheckingEnabled(boolean)`

### accessibleContext

    protected AccessibleContext accessibleContext

Constructor Detail

### JApplet

    public JApplet()
            throws HeadlessException

  Creates a swing applet instance.

  This constructor sets the component's locale property to the value returned by `JComponent.getDefaultLocale`.

Throws:
  `HeadlessException` - if GraphicsEnvironment.isHeadless() returns true.
See Also:
  `GraphicsEnvironment.isHeadless()`, `JComponent.getDefaultLocale()`

Method Detail

### createRootPane

    protected JRootPane createRootPane()

  Called by the constructor methods to create the default rootPane.

### update

    public void update(Graphics g)

  Just calls `paint(g)`. This method was overridden to prevent an unnecessary call to clear the background.

  Overrides:
    `update` in class `Container`
  Parameters:
    `g` - the specified Graphics window
  See Also:
    `Component.update(Graphics)`

### setJMenuBar

    public void setJMenuBar(JMenuBar menuBar)

  Sets the menubar for this applet.

  Parameters:
    `menuBar` - the menubar being placed in the applet
  See Also:
    `getJMenuBar()`

### getJMenuBar

    public JMenuBar getJMenuBar()

  Returns the menubar set on this applet.

  See Also:
    `setJMenuBar(javax.swing.JMenuBar)`

### isRootPaneCheckingEnabled

    protected boolean isRootPaneCheckingEnabled()

  Returns:
    true if add and setLayout should be checked
  See Also:
    `addImpl(java.awt.Component, java.lang.Object, int)`, `setLayout(java.awt.LayoutManager)`, `setRootPaneCheckingEnabled(boolean)`

### setRootPaneCheckingEnabled

    protected void setRootPaneCheckingEnabled(boolean enabled)

  If true then calls to add() and setLayout() will cause an exception to be thrown.

  See Also:
    `addImpl(java.awt.Component, java.lang.Object, int)`, `setLayout(java.awt.LayoutManager)`, `isRootPaneCheckingEnabled()`

### addImpl

    protected void addImpl(Component comp,
                           Object constraints,
                           int index)

  By default, children may not be added directly to a this component, they must be added to its contentPane instead. For example:

       thiComponent.getContentPane().add(child)

  An attempt to add to directly to this component will cause an runtime exception to be thrown. Subclasses can disable this behavior.

  Overrides:
    `addImpl` in class `Container`
  Parameters:
    `comp` - the component to be added
    `constraints` - an object expressing layout constraints for this component
    `index` - the position in the container's list at which to insert the component, where `-1` means append to the end
  Throws:
    `Error` - if called with rootPaneChecking true
  See Also:
    `setRootPaneCheckingEnabled(boolean)`

### remove

    public void remove(Component comp)

  Removes the specified component from this container.

  Overrides:
    `remove` in class `Container`
  Parameters:
    `comp` - the component to be removed
  See Also:
    `Container.add(java.awt.Component)`

### setLayout

    public void setLayout(LayoutManager manager)

  By default the layout of this component may not be set, the layout of its contentPane should be set instead. For example:

       thisComponent.getContentPane().setLayout(new GridLayout(1, 2))

  An attempt to set the layout of this component will cause an runtime exception to be thrown. Subclasses can disable this behavior.

  Overrides:
    `setLayout` in class `Container`
  Parameters:
    `manager` - the specified layout manager
  Throws:
    `Error` - if called with rootPaneChecking true
  See Also:
    `setRootPaneCheckingEnabled(boolean)`

### getRootPane

    public JRootPane getRootPane()

  Returns the rootPane object for this applet.

  Specified by:
    `getRootPane` in interface `RootPaneContainer`
  Returns:
    this components single JRootPane child.
  See Also:
    `setRootPane(javax.swing.JRootPane)`, `RootPaneContainer.getRootPane()`

### setRootPane

    protected void setRootPane(JRootPane root)

  Sets the rootPane property. This method is called by the constructor.

  Parameters:
    `root` - the rootPane object for this applet
  See Also:
    `getRootPane()`

### getContentPane

    public Container getContentPane()

  Returns the contentPane object for this applet.

  Specified by:
    `getContentPane` in interface `RootPaneContainer`
  Returns:
    the value of the contentPane property.
  See Also:
    `setContentPane(java.awt.Container)`, `RootPaneContainer.getContentPane()`

### setContentPane

    public void setContentPane(Container contentPane)

  Sets the contentPane property. This method is called by the constructor.

  Specified by:
    `setContentPane` in interface `RootPaneContainer`
  Parameters:
    `contentPane` - the contentPane object for this applet
  Throws:
    `IllegalComponentStateException` - (a runtime exception) if the content pane parameter is null
  See Also:
    `getContentPane()`, `RootPaneContainer.setContentPane(java.awt.Container)`

### getLayeredPane

    public JLayeredPane getLayeredPane()

  Returns the layeredPane object for this applet.

  Specified by:
    `getLayeredPane` in interface `RootPaneContainer`
  Returns:
    the value of the layeredPane property.
  Throws:
    `IllegalComponentStateException` - (a runtime exception) if the layered pane parameter is null
  See Also:
    `setLayeredPane(javax.swing.JLayeredPane)`, `RootPaneContainer.getLayeredPane()`

### setLayeredPane

    public void setLayeredPane(JLayeredPane layeredPane)

  Sets the layeredPane property. This method is called by the constructor.

  Specified by:
    `setLayeredPane` in interface `RootPaneContainer`
  Parameters:
    `layeredPane` - the layeredPane object for this applet
  See Also:
    `getLayeredPane()`, `RootPaneContainer.setLayeredPane(javax.swing.JLayeredPane)`

### getGlassPane

    public Component getGlassPane()

  Returns the glassPane object for this applet.

  Specified by:
    `getGlassPane` in interface `RootPaneContainer`
  Returns:
    the value of the glassPane property.
  See Also:
    `setGlassPane(java.awt.Component)`, `RootPaneContainer.getGlassPane()`

### setGlassPane

    public void setGlassPane(Component glassPane)

  Sets the glassPane property. This method is called by the constructor.

  Specified by:
    `setGlassPane` in interface `RootPaneContainer`
  Parameters:
    `glassPane` - the glassPane object for this applet
  See Also:
    `getGlassPane()`, `RootPaneContainer.setGlassPane(java.awt.Component)`

### paramString

    protected String paramString()

  Returns a string representation of this JApplet. This method is intended to be used only for debugging purposes, and the content and format of the returned string may vary between implementations. The returned string may be empty but may not be `null`.

  Overrides:
    `paramString` in class `Container`
  Returns:
    a string representation of this JApplet.

### getAccessibleContext

    public AccessibleContext getAccessibleContext()

  Gets the AccessibleContext associated with this JApplet. For JApplets, the AccessibleContext takes the form of an AccessibleJApplet. A new AccessibleJApplet instance is created if necessary.

  Specified by:
    `getAccessibleContext` in interface `Accessible`
  Overrides:
    `getAccessibleContext` in class `Applet`
  Returns:
    an AccessibleJApplet that serves as the AccessibleContext of this JApplet

Overview | Package | Class | Use | Tree | Deprecated | Index | Help
| JavaTM 2 Platform Std. Ed. v1.4.2
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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.

Copyright 2003 Sun Microsystems, Inc. All rights reserved. Use is subject to license terms. Also see the documentation redistribution policy.