Module java.desktop
Package javax.swing

# Class JButton

java.lang.Object
java.awt.Component
java.awt.Container
javax.swing.JComponent
javax.swing.AbstractButton
javax.swing.JButton

All Implemented Interfaces:
  `ImageObserver`, `ItemSelectable`, `MenuContainer`, `Serializable`, `Accessible`, `SwingConstants`

Direct Known Subclasses:
  `BasicArrowButton`, `MetalComboBoxButton`

@JavaBean(defaultProperty="UIClassID", description="An implementation of a \"push\" button.") public class JButton extends AbstractButton implements Accessible
An implementation of a "push" button.

Buttons can be configured, and to some degree controlled, by `Action`s. Using an `Action` with a button has many benefits beyond directly configuring a button. Refer to Swing Components Supporting `Action` for more details, and you can find more information in How to Use Actions, a section in The Java Tutorial.

See How to Use Buttons, Check Boxes, and Radio Buttons in The Java Tutorial for information and examples of using buttons.

Warning: Swing is not thread safe. For more information see Swing's Threading Policy.

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 JavaBeans has been added to the `java.beans` package. Please see `XMLEncoder`.

Since:
  1.2

## Nested Class Summary

Nested Classes
Modifier and Type
Class
Description
`protected class`
`JButton.AccessibleJButton`
This class implements accessibility support for the `JButton` class.

## Nested classes/interfaces declared in class javax.swing.AbstractButton

`AbstractButton.AccessibleAbstractButton, AbstractButton.ButtonChangeListener`

## Nested classes/interfaces declared in class javax.swing.JComponent

`JComponent.AccessibleJComponent`

## Nested classes/interfaces declared in class java.awt.Container

`Container.AccessibleAWTContainer`

## Nested classes/interfaces declared in class java.awt.Component

`Component.AccessibleAWTComponent, Component.BaselineResizeBehavior, Component.BltBufferStrategy, Component.FlipBufferStrategy`

## Field Summary

### Fields declared in class javax.swing.AbstractButton

`actionListener, BORDER_PAINTED_CHANGED_PROPERTY, changeEvent, changeListener, CONTENT_AREA_FILLED_CHANGED_PROPERTY, DISABLED_ICON_CHANGED_PROPERTY, DISABLED_SELECTED_ICON_CHANGED_PROPERTY, FOCUS_PAINTED_CHANGED_PROPERTY, HORIZONTAL_ALIGNMENT_CHANGED_PROPERTY, HORIZONTAL_TEXT_POSITION_CHANGED_PROPERTY, ICON_CHANGED_PROPERTY, itemListener, MARGIN_CHANGED_PROPERTY, MNEMONIC_CHANGED_PROPERTY, model, MODEL_CHANGED_PROPERTY, PRESSED_ICON_CHANGED_PROPERTY, ROLLOVER_ENABLED_CHANGED_PROPERTY, ROLLOVER_ICON_CHANGED_PROPERTY, ROLLOVER_SELECTED_ICON_CHANGED_PROPERTY, SELECTED_ICON_CHANGED_PROPERTY, TEXT_CHANGED_PROPERTY, VERTICAL_ALIGNMENT_CHANGED_PROPERTY, VERTICAL_TEXT_POSITION_CHANGED_PROPERTY`

### Fields declared in class javax.swing.JComponent

`listenerList, TOOL_TIP_TEXT_KEY, ui, UNDEFINED_CONDITION, WHEN_ANCESTOR_OF_FOCUSED_COMPONENT, WHEN_FOCUSED, WHEN_IN_FOCUSED_WINDOW`

### Fields declared in class java.awt.Component

`accessibleContext, BOTTOM_ALIGNMENT, CENTER_ALIGNMENT, LEFT_ALIGNMENT, RIGHT_ALIGNMENT, TOP_ALIGNMENT`

### Fields declared in interface java.awt.image.ImageObserver

`ABORT, ALLBITS, ERROR, FRAMEBITS, HEIGHT, PROPERTIES, SOMEBITS, WIDTH`

### Fields declared in interface javax.swing.SwingConstants

`BOTTOM, CENTER, EAST, HORIZONTAL, LEADING, LEFT, NEXT, NORTH, NORTH_EAST, NORTH_WEST, PREVIOUS, RIGHT, SOUTH, SOUTH_EAST, SOUTH_WEST, TOP, TRAILING, VERTICAL, WEST`

## Constructor Summary

Constructors
Constructor
Description
`JButton()`
Creates a button with no set text or icon.
`JButton(String text)`
Creates a button with text.
`JButton(String text, Icon icon)`
Creates a button with initial text and an icon.
`JButton(Action a)`
Creates a button where properties are taken from the `Action` supplied.
`JButton(Icon icon)`
Creates a button with an icon.

## Method Summary

Modifier and Type
Method
Description
`AccessibleContext`
`getAccessibleContext()`
Gets the `AccessibleContext` associated with this `JButton`.
`String`
`getUIClassID()`
Returns a string that specifies the name of the L&F class that renders this component.
`boolean`
`isDefaultButton()`
Gets the value of the `defaultButton` property, which if `true` means that this button is the current default button for its `JRootPane`.
`boolean`
`isDefaultCapable()`
Gets the value of the `defaultCapable` property.
`protected String`
`paramString()`
Returns a string representation of this `JButton`.
`void`
`removeNotify()`
Overrides `JComponent.removeNotify` to check if this button is currently set as the default button on the `RootPane`, and if so, sets the `RootPane`'s default button to `null` to ensure the `RootPane` doesn't hold onto an invalid button reference.
`void`
`setDefaultCapable(boolean defaultCapable)`
Sets the `defaultCapable` property, which determines whether this button can be made the default button for its root pane.
`void`
`updateUI()`
Resets the UI property to a value from the current look and feel.

### Methods declared in class javax.swing.AbstractButton

`actionPropertyChanged, addActionListener, addChangeListener, addImpl, addItemListener, checkHorizontalKey, checkVerticalKey, configurePropertiesFromAction, createActionListener, createActionPropertyChangeListener, createChangeListener, createItemListener, doClick, doClick, fireActionPerformed, fireItemStateChanged, fireStateChanged, getAction, getActionCommand, getActionListeners, getChangeListeners, getDisabledIcon, getDisabledSelectedIcon, getDisplayedMnemonicIndex, getHideActionText, getHorizontalAlignment, getHorizontalTextPosition, getIcon, getIconTextGap, getItemListeners, getLabel, getMargin, getMnemonic, getModel, getMultiClickThreshhold, getPressedIcon, getRolloverIcon, getRolloverSelectedIcon, getSelectedIcon, getSelectedObjects, getText, getUI, getVerticalAlignment, getVerticalTextPosition, imageUpdate, init, isBorderPainted, isContentAreaFilled, isFocusPainted, isRolloverEnabled, isSelected, paintBorder, removeActionListener, removeChangeListener, removeItemListener, setAction, setActionCommand, setBorderPainted, setContentAreaFilled, setDisabledIcon, setDisabledSelectedIcon, setDisplayedMnemonicIndex, setEnabled, setFocusPainted, setHideActionText, setHorizontalAlignment, setHorizontalTextPosition, setIcon, setIconTextGap, setLabel, setLayout, setMargin, setMnemonic, setMnemonic, setModel, setMultiClickThreshhold, setPressedIcon, setRolloverEnabled, setRolloverIcon, setRolloverSelectedIcon, setSelected, setSelectedIcon, setText, setUI, setVerticalAlignment, setVerticalTextPosition`

### Methods declared in class javax.swing.JComponent

`addAncestorListener, addNotify, addVetoableChangeListener, computeVisibleRect, contains, createToolTip, disable, enable, firePropertyChange, firePropertyChange, fireVetoableChange, getActionForKeyStroke, getActionMap, getAlignmentX, getAlignmentY, getAncestorListeners, getAutoscrolls, getBaseline, getBaselineResizeBehavior, getBorder, getBounds, getClientProperty, getComponentGraphics, getComponentPopupMenu, getConditionForKeyStroke, getDebugGraphicsOptions, getDefaultLocale, getFontMetrics, getGraphics, getHeight, getInheritsPopupMenu, getInputMap, getInputMap, getInputVerifier, getInsets, getInsets, getListeners, getLocation, getMaximumSize, getMinimumSize, getNextFocusableComponent, getPopupLocation, getPreferredSize, getRegisteredKeyStrokes, getRootPane, getSize, getToolTipLocation, getToolTipText, getToolTipText, getTopLevelAncestor, getTransferHandler, getVerifyInputWhenFocusTarget, getVetoableChangeListeners, getVisibleRect, getWidth, getX, getY, grabFocus, hide, isDoubleBuffered, isLightweightComponent, isManagingFocus, isOpaque, isOptimizedDrawingEnabled, isPaintingForPrint, isPaintingOrigin, isPaintingTile, isRequestFocusEnabled, isValidateRoot, paint, paintChildren, paintComponent, paintImmediately, paintImmediately, print, printAll, printBorder, printChildren, printComponent, processComponentKeyEvent, processKeyBinding, processKeyEvent, processMouseEvent, processMouseMotionEvent, putClientProperty, registerKeyboardAction, registerKeyboardAction, removeAncestorListener, removeVetoableChangeListener, repaint, repaint, requestDefaultFocus, requestFocus, requestFocus, requestFocusInWindow, requestFocusInWindow, resetKeyboardActions, reshape, revalidate, scrollRectToVisible, setActionMap, setAlignmentX, setAlignmentY, setAutoscrolls, setBackground, setBorder, setComponentPopupMenu, setDebugGraphicsOptions, setDefaultLocale, setDoubleBuffered, setFocusTraversalKeys, setFont, setForeground, setInheritsPopupMenu, setInputMap, setInputVerifier, setMaximumSize, setMinimumSize, setNextFocusableComponent, setOpaque, setPreferredSize, setRequestFocusEnabled, setToolTipText, setTransferHandler, setUI, setVerifyInputWhenFocusTarget, setVisible, unregisterKeyboardAction, update`

### Methods declared in class java.awt.Container

`add, add, add, add, add, addContainerListener, addPropertyChangeListener, addPropertyChangeListener, applyComponentOrientation, areFocusTraversalKeysSet, countComponents, deliverEvent, doLayout, findComponentAt, findComponentAt, getComponent, getComponentAt, getComponentAt, getComponentCount, getComponents, getComponentZOrder, getContainerListeners, getFocusTraversalKeys, getFocusTraversalPolicy, getLayout, getMousePosition, insets, invalidate, isAncestorOf, isFocusCycleRoot, isFocusCycleRoot, isFocusTraversalPolicyProvider, isFocusTraversalPolicySet, layout, list, list, locate, minimumSize, paintComponents, preferredSize, printComponents, processContainerEvent, processEvent, remove, remove, removeAll, removeContainerListener, setComponentZOrder, setFocusCycleRoot, setFocusTraversalPolicy, setFocusTraversalPolicyProvider, transferFocusDownCycle, validate, validateTree`

### Methods declared in class java.awt.Component

`action, add, addComponentListener, addFocusListener, addHierarchyBoundsListener, addHierarchyListener, addInputMethodListener, addKeyListener, addMouseListener, addMouseMotionListener, addMouseWheelListener, bounds, checkImage, checkImage, coalesceEvents, contains, createImage, createImage, createVolatileImage, createVolatileImage, disableEvents, dispatchEvent, enable, enableEvents, enableInputMethods, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, firePropertyChange, getBackground, getBounds, getColorModel, getComponentListeners, getComponentOrientation, getCursor, getDropTarget, getFocusCycleRootAncestor, getFocusListeners, getFocusTraversalKeysEnabled, getFont, getForeground, getGraphicsConfiguration, getHierarchyBoundsListeners, getHierarchyListeners, getIgnoreRepaint, getInputContext, getInputMethodListeners, getInputMethodRequests, getKeyListeners, getLocale, getLocation, getLocationOnScreen, getMouseListeners, getMouseMotionListeners, getMousePosition, getMouseWheelListeners, getName, getParent, getPropertyChangeListeners, getPropertyChangeListeners, getSize, getToolkit, getTreeLock, gotFocus, handleEvent, hasFocus, inside, isBackgroundSet, isCursorSet, isDisplayable, isEnabled, isFocusable, isFocusOwner, isFocusTraversable, isFontSet, isForegroundSet, isLightweight, isMaximumSizeSet, isMinimumSizeSet, isPreferredSizeSet, isShowing, isValid, isVisible, keyDown, keyUp, list, list, list, location, lostFocus, mouseDown, mouseDrag, mouseEnter, mouseExit, mouseMove, mouseUp, move, nextFocus, paintAll, postEvent, prepareImage, prepareImage, processComponentEvent, processFocusEvent, processHierarchyBoundsEvent, processHierarchyEvent, processInputMethodEvent, processMouseWheelEvent, remove, removeComponentListener, removeFocusListener, removeHierarchyBoundsListener, removeHierarchyListener, removeInputMethodListener, removeKeyListener, removeMouseListener, removeMouseMotionListener, removeMouseWheelListener, removePropertyChangeListener, removePropertyChangeListener, repaint, repaint, repaint, requestFocus, requestFocus, requestFocusInWindow, resize, resize, setBounds, setBounds, setComponentOrientation, setCursor, setDropTarget, setFocusable, setFocusTraversalKeysEnabled, setIgnoreRepaint, setLocale, setLocation, setLocation, setMixingCutoutShape, setName, setSize, setSize, show, show, size, toString, transferFocus, transferFocusBackward, transferFocusUpCycle`

### Methods declared in class java.lang.Object

`clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait`

## Constructor Details

### JButton

public JButton()
Creates a button with no set text or icon.

### JButton

public JButton(Icon icon)
Creates a button with an icon.

Parameters:
  `icon` - the Icon image to display on the button

### JButton

@ConstructorProperties("text") public JButton(String text)
Creates a button with text.

Parameters:
  `text` - the text of the button

### JButton

public JButton(Action a)
Creates a button where properties are taken from the `Action` supplied.

Parameters:
  `a` - the `Action` used to specify the new button
Since:
  1.3

### JButton

public JButton(String text, Icon icon)
Creates a button with initial text and an icon.

Parameters:
  `text` - the text of the button
  `icon` - the Icon image to display on the button

## Method Details

### updateUI

public void updateUI()
Resets the UI property to a value from the current look and feel.

Overrides:
  `updateUI` in class `AbstractButton`
See Also:
  - `JComponent.updateUI()`

### getUIClassID

@BeanProperty(bound=false, expert=true, description="A string that specifies the name of the L&F class.") public String getUIClassID()
Returns a string that specifies the name of the L&F class that renders this component.

Overrides:
  `getUIClassID` in class `JComponent`
Returns:
  the string "ButtonUI"
See Also:
  - `JComponent.getUIClassID()`
  - `UIDefaults.getUI(javax.swing.JComponent)`

### isDefaultButton

@BeanProperty(bound=false, description="Whether or not this button is the default button") public boolean isDefaultButton()
Gets the value of the `defaultButton` property, which if `true` means that this button is the current default button for its `JRootPane`. Most look and feels render the default button differently, and may potentially provide bindings to access the default button.

Returns:
  the value of the `defaultButton` property
See Also:
  - `JRootPane.setDefaultButton(javax.swing.JButton)`
  - `isDefaultCapable()`

### isDefaultCapable

public boolean isDefaultCapable()
Gets the value of the `defaultCapable` property.

Returns:
  the value of the `defaultCapable` property
See Also:
  - `setDefaultCapable(boolean)`
  - `isDefaultButton()`
  - `JRootPane.setDefaultButton(javax.swing.JButton)`

### setDefaultCapable

@BeanProperty(visualUpdate=true, description="Whether or not this button can be the default button") public void setDefaultCapable(boolean defaultCapable)
Sets the `defaultCapable` property, which determines whether this button can be made the default button for its root pane. The default value of the `defaultCapable` property is `true` unless otherwise specified by the look and feel.

Parameters:
  `defaultCapable` - `true` if this button will be capable of being the default button on the `RootPane`; otherwise `false`
See Also:
  - `isDefaultCapable()`

### removeNotify

public void removeNotify()
Overrides `JComponent.removeNotify` to check if this button is currently set as the default button on the `RootPane`, and if so, sets the `RootPane`'s default button to `null` to ensure the `RootPane` doesn't hold onto an invalid button reference.

Overrides:
  `removeNotify` in class `AbstractButton`
See Also:
  - `JComponent.registerKeyboardAction(java.awt.event.ActionListener, java.lang.String, javax.swing.KeyStroke, int)`

### paramString

protected String paramString()
Returns a string representation of this `JButton`. 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 `AbstractButton`
Returns:
  a string representation of this `JButton`

### getAccessibleContext

@BeanProperty(bound=false, expert=true, description="The AccessibleContext associated with this Button.") public AccessibleContext getAccessibleContext()
Gets the `AccessibleContext` associated with this `JButton`. For `JButton`s, the `AccessibleContext` takes the form of an `AccessibleJButton`. A new `AccessibleJButton` instance is created if necessary.

Specified by:
  `getAccessibleContext` in interface `Accessible`
Overrides:
  `getAccessibleContext` in class `Component`
Returns:
  an `AccessibleJButton` that serves as the `AccessibleContext` of this `JButton`