Module java.desktop

# Package javax.swing

package javax.swing
Provides a set of "lightweight" (all-Java language) components that, to the maximum degree possible, work the same on all platforms. For a programmer's guide to using these components, see Creating a GUI with JFC/Swing, a trail in The Java Tutorial. For other resources, see Related Documentation.

## Swing's Threading Policy

In general Swing is not thread safe. All Swing components and related classes, unless otherwise documented, must be accessed on the event dispatching thread.

Typical Swing applications do processing in response to an event generated from a user gesture. For example, clicking on a `JButton` notifies all `ActionListeners` added to the `JButton`. As all events generated from a user gesture are dispatched on the event dispatching thread, most developers are not impacted by the restriction.

Where the impact lies, however, is in constructing and showing a Swing application. Calls to an application's `main` method, or methods in `Applet`, are not invoked on the event dispatching thread. As such, care must be taken to transfer control to the event dispatching thread when constructing and showing an application or applet. The preferred way to transfer control and begin working with Swing is to use `invokeLater`. The `invokeLater` method schedules a `Runnable` to be processed on the event dispatching thread. The following two examples work equally well for transferring control and starting up a Swing application:

     import javax.swing.SwingUtilities;

     public class MyApp implements Runnable {
         public void run() {
             // Invoked on the event dispatching thread.
             // Construct and show GUI.
         }

         public static void main(String[] args) {
             SwingUtilities.invokeLater(new MyApp());
         }
     }

Or:

     import javax.swing.SwingUtilities;

     public class MyApp {
         MyApp(String[] args) {
             // Invoked on the event dispatching thread.
             // Do any initialization here.
         }

         public void show() {
             // Show the UI.
         }

         public static void main(final String[] args) {
             // Schedule a job for the event-dispatching thread:
             // creating and showing this application's GUI.
             SwingUtilities.invokeLater(new Runnable() {
                 public void run() {
                     new MyApp(args).show();
                 }
             });
         }
     }

This restriction also applies to models attached to Swing components. For example, if a `TableModel` is attached to a `JTable`, the `TableModel` should only be modified on the event dispatching thread. If you modify the model on a separate thread you run the risk of exceptions and possible display corruption.

Although it is generally safe to make updates to the UI immediately, when executing on the event dispatch thread, there is an exception : if a model listener tries to further change the UI before the UI has been updated to reflect a pending change then the UI may render incorrectly. This can happen if an application installed listener needs to update the UI in response to an event which will cause a change in the model structure. It is important to first allow component installed listeners to process this change, since there is no guarantee of the order in which listeners may be called. The solution is for the application listener to make the change using `SwingUtilities.invokeLater(Runnable)` so that any changes to UI rendering will be done post processing all the model listeners installed by the component.

As all events are delivered on the event dispatching thread, care must be taken in event processing. In particular, a long running task, such as network io or computational intensive processing, executed on the event dispatching thread blocks the event dispatching thread from dispatching any other events. While the event dispatching thread is blocked the application is completely unresponsive to user input. Refer to `SwingWorker` for the preferred way to do such processing when working with Swing.

More information on this topic can be found in the Swing tutorial, in particular the section on Concurrency in Swing.

## Related Documentation

For overviews, tutorials, examples, guides, and other documentation, please see:

- The Swing Connection
- The Java Tutorial
- Online Training at the Java Developer Connection SM
- Java Foundation Classes (JFC) home page

- Related Packages
  Package
  Description
  javax.swing.border
  Provides classes and interface for drawing specialized borders around a Swing component.
  javax.swing.colorchooser
  Contains classes and interfaces used by the `JColorChooser` component.
  javax.swing.event
  Provides for events fired by Swing components.
  javax.swing.filechooser
  Contains classes and interfaces used by the `JFileChooser` component.
  javax.swing.plaf
  Provides one interface and many abstract classes that Swing uses to provide its pluggable look-and-feel capabilities.
  javax.swing.table
  Provides classes and interfaces for dealing with `javax.swing.JTable`.
  javax.swing.text
  Provides classes and interfaces that deal with editable and noneditable text components.
  javax.swing.tree
  Provides classes and interfaces for dealing with `javax.swing.JTree`.
  javax.swing.undo
  Allows developers to provide support for undo/redo in applications such as text editors.
- Class
  Description
  AbstractAction
  This class provides default implementations for the JFC `Action` interface.
  AbstractButton
  Defines common behaviors for buttons and menu items.
  AbstractCellEditor
  A base class for `CellEditors`, providing default implementations for the methods in the `CellEditor` interface except `getCellEditorValue()`.
  AbstractListModel<E>
  The abstract definition for the data model that provides a `List` with its contents.
  AbstractSpinnerModel
  This class provides the ChangeListener part of the SpinnerModel interface that should be suitable for most concrete SpinnerModel implementations.
  Action
  The `Action` interface provides a useful extension to the `ActionListener` interface in cases where the same functionality may be accessed by several controls.
  ActionMap
  `ActionMap` provides mappings from `Object`s (called keys or `Action` names) to `Action`s.
  BorderFactory
  Factory class for vending standard `Border` objects.
  BoundedRangeModel
  Defines the data model used by components like `Slider`s and `ProgressBar`s.
  Box
  A lightweight container that uses a BoxLayout object as its layout manager.
  Box.Filler
  An implementation of a lightweight component that participates in layout but has no view.
  BoxLayout
  A layout manager that allows multiple components to be laid out either vertically or horizontally.
  ButtonGroup
  This class is used to create a multiple-exclusion scope for a set of buttons.
  ButtonModel
  State model for buttons.
  CellEditor
  This interface defines the methods any general editor should be able to implement.
  CellRendererPane
  This class is inserted in between cell renderers and the components that use them.
  ComboBoxEditor
  The editor component used for JComboBox components.
  ComboBoxModel<E>
  A data model for a combo box.
  ComponentInputMap
  A `ComponentInputMap` is an `InputMap` associated with a particular `JComponent`.
  DebugGraphics
  Graphics subclass supporting graphics debugging.
  DefaultBoundedRangeModel
  A generic implementation of BoundedRangeModel.
  DefaultButtonModel
  The default implementation of a `Button` component's data model.
  DefaultCellEditor
  The default editor for table and tree cells.
  DefaultComboBoxModel<E>
  The default model for combo boxes.
  DefaultDesktopManager
  This is an implementation of the `DesktopManager`.
  DefaultFocusManager
  This class has been obsoleted by the 1.4 focus APIs.
  DefaultListCellRenderer
  Renders an item in a list.
  DefaultListCellRenderer.UIResource
  A subclass of DefaultListCellRenderer that implements UIResource.
  DefaultListModel<E>
  This class loosely implements the `java.util.Vector` API, in that it implements the 1.1.x version of `java.util.Vector`, has no collection class support, and notifies the `ListDataListener`s when changes occur.
  DefaultListSelectionModel
  Default data model for list selections.
  DefaultRowSorter<M,I>
  An implementation of `RowSorter` that provides sorting and filtering around a grid-based data model.
  DefaultRowSorter.ModelWrapper<M,I>
  `DefaultRowSorter.ModelWrapper` is responsible for providing the data that gets sorted by `DefaultRowSorter`.
  DefaultSingleSelectionModel
  A generic implementation of SingleSelectionModel.
  DesktopManager
  DesktopManager objects are owned by a JDesktopPane object.
  DropMode
  Drop modes, used to determine the method by which a component tracks and indicates a drop location during drag and drop.
  FocusManager
  This class has been obsoleted by the 1.4 focus APIs.
  GrayFilter
  An image filter that "disables" an image by turning it into a grayscale image, and brightening the pixels in the image.
  GroupLayout
  `GroupLayout` is a `LayoutManager` that hierarchically groups components in order to position them in a `Container`.
  GroupLayout.Alignment
  Enumeration of the possible ways `ParallelGroup` can align its children.
  Icon
  A small fixed size picture, typically used to decorate components.
  ImageIcon
  An implementation of the Icon interface that paints Icons from Images.
  InputMap
  `InputMap` provides a binding between an input event (currently only `KeyStroke`s are used) and an `Object`.
  InputVerifier
  This class provides the validation mechanism for Swing components.
  InternalFrameFocusTraversalPolicy
  A FocusTraversalPolicy which can optionally provide an algorithm for determining a JInternalFrame's initial Component.
  JApplet
  Deprecated, for removal: This API element is subject to removal in a future version.
  The Applet API is deprecated, no replacement.
  JButton
  An implementation of a "push" button.
  JCheckBox
  An implementation of a check box -- an item that can be selected or deselected, and which displays its state to the user.
  JCheckBoxMenuItem
  A menu item that can be selected or deselected.
  JColorChooser
  `JColorChooser` provides a pane of controls designed to allow a user to manipulate and select a color.
  JComboBox<E>
  A component that combines a button or editable field and a drop-down list.
  JComboBox.KeySelectionManager
  The interface that defines a `KeySelectionManager`.
  JComponent
  The base class for all Swing components except top-level containers.
  JDesktopPane
  A container used to create a multiple-document interface or a virtual desktop.
  JDialog
  The main class for creating a dialog window.
  JEditorPane
  A text component to edit various kinds of content.
  JFileChooser
  `JFileChooser` provides a simple mechanism for the user to choose a file.
  JFormattedTextField
  `JFormattedTextField` extends `JTextField` adding support for formatting arbitrary values, as well as retrieving a particular object once the user has edited the text.
  JFormattedTextField.AbstractFormatter
  Instances of `AbstractFormatter` are used by `JFormattedTextField` to handle the conversion both from an Object to a String, and back from a String to an Object.
  JFormattedTextField.AbstractFormatterFactory
  Instances of `AbstractFormatterFactory` are used by `JFormattedTextField` to obtain instances of `AbstractFormatter` which in turn are used to format values.
  JFrame
  An extended version of `java.awt.Frame` that adds support for the JFC/Swing component architecture.
  JInternalFrame
  A lightweight object that provides many of the features of a native frame, including dragging, closing, becoming an icon, resizing, title display, and support for a menu bar.
  JInternalFrame.JDesktopIcon
  This component represents an iconified version of a `JInternalFrame`.
  JLabel
  A display area for a short text string or an image, or both.
  JLayer<V extends Component>
  `JLayer` is a universal decorator for Swing components which enables you to implement various advanced painting effects as well as receive notifications of all `AWTEvent`s generated within its borders.
  JLayeredPane
  `JLayeredPane` adds depth to a JFC/Swing container, allowing components to overlap each other when needed.
  JList<E>
  A component that displays a list of objects and allows the user to select one or more items.
  JList.DropLocation
  A subclass of `TransferHandler.DropLocation` representing a drop location for a `JList`.
  JMenu
  An implementation of a menu -- a popup window containing `JMenuItem`s that is displayed when the user selects an item on the `JMenuBar`.
  JMenuBar
  An implementation of a menu bar.
  JMenuItem
  An implementation of an item in a menu.
  JOptionPane
  `JOptionPane` makes it easy to pop up a standard dialog box that prompts users for a value or informs them of something.
  JPanel
  `JPanel` is a generic lightweight container.
  JPasswordField
  `JPasswordField` is a lightweight component that allows the editing of a single line of text where the view indicates something was typed, but does not show the original characters.
  JPopupMenu
  An implementation of a popup menu -- a small window that pops up and displays a series of choices.
  JPopupMenu.Separator
  A popup menu-specific separator.
  JProgressBar
  A component that visually displays the progress of some task.
  JRadioButton
  An implementation of a radio button -- an item that can be selected or deselected, and which displays its state to the user.
  JRadioButtonMenuItem
  An implementation of a radio button menu item.
  JRootPane
  A lightweight container used behind the scenes by `JFrame`, `JDialog`, `JWindow`, `JApplet`, and `JInternalFrame`.
  JScrollBar
  An implementation of a scrollbar.
  JScrollPane
  Provides a scrollable view of a lightweight component.
  JSeparator
  `JSeparator` provides a general purpose component for implementing divider lines - most commonly used as a divider between menu items that breaks them up into logical groupings.
  JSlider
  A component that lets the user graphically select a value by sliding a knob within a bounded interval.
  JSpinner
  A single line input field that lets the user select a number or an object value from an ordered sequence.
  JSpinner.DateEditor
  An editor for a `JSpinner` whose model is a `SpinnerDateModel`.
  JSpinner.DefaultEditor
  A simple base class for more specialized editors that displays a read-only view of the model's current value with a `JFormattedTextField`.
  JSpinner.ListEditor
  An editor for a `JSpinner` whose model is a `SpinnerListModel`.
  JSpinner.NumberEditor
  An editor for a `JSpinner` whose model is a `SpinnerNumberModel`.
  JSplitPane
  `JSplitPane` is used to divide two (and only two) `Component`s.
  JTabbedPane
  A component that lets the user switch between a group of components by clicking on a tab with a given title and/or icon.
  JTable
  The `JTable` is used to display and edit regular two-dimensional tables of cells.
  JTable.DropLocation
  A subclass of `TransferHandler.DropLocation` representing a drop location for a `JTable`.
  JTable.PrintMode
  Printing modes, used in printing `JTable`s.
  JTextArea
  A `JTextArea` is a multi-line area that displays plain text.
  JTextField
  `JTextField` is a lightweight component that allows the editing of a single line of text.
  JTextPane
  A text component that can be marked up with attributes that are represented graphically.
  JToggleButton
  An implementation of a two-state button.
  JToggleButton.ToggleButtonModel
  The ToggleButton model
  JToolBar
  `JToolBar` provides a component that is useful for displaying commonly used `Action`s or controls.
  JToolBar.Separator
  A toolbar-specific separator.
  JToolTip
  Used to display a "Tip" for a Component.
  JTree
  A control that displays a set of hierarchical data as an outline.
  JTree.DropLocation
  A subclass of `TransferHandler.DropLocation` representing a drop location for a `JTree`.
  JTree.DynamicUtilTreeNode
  `DynamicUtilTreeNode` can wrap vectors/hashtables/arrays/strings and create the appropriate children tree nodes as necessary.
  JTree.EmptySelectionModel
  `EmptySelectionModel` is a `TreeSelectionModel` that does not allow anything to be selected.
  JViewport
  The "viewport" or "porthole" through which you see the underlying information.
  JWindow
  A `JWindow` is a container that can be displayed anywhere on the user's desktop.
  KeyStroke
  A KeyStroke represents a key action on the keyboard, or equivalent input device.
  LayoutFocusTraversalPolicy
  A SortingFocusTraversalPolicy which sorts Components based on their size, position, and orientation.
  LayoutStyle
  `LayoutStyle` provides information about how to position components.
  LayoutStyle.ComponentPlacement
  `ComponentPlacement` is an enumeration of the possible ways two components can be placed relative to each other.
  ListCellRenderer<E>
  Identifies components that can be used as "rubber stamps" to paint the cells in a JList.
  ListModel<E>
  This interface defines the methods components like JList use to get the value of each cell in a list and the length of the list.
  ListSelectionModel
  This interface represents the current state of the selection for any of the components that display a list of values with stable indices.
  LookAndFeel
  `LookAndFeel`, as the name implies, encapsulates a look and feel.
  MenuElement
  Any component that can be placed into a menu should implement this interface.
  MenuSelectionManager
  A MenuSelectionManager owns the selection in menu hierarchy.
  MutableComboBoxModel<E>
  A mutable version of `ComboBoxModel`.
  OverlayLayout
  A layout manager to arrange components over the top of each other.
  Painter<T>
  A painting delegate.
  Popup
  Popups are used to display a `Component` to the user, typically on top of all the other `Component`s in a particular containment hierarchy.
  PopupFactory
  `PopupFactory`, as the name implies, is used to obtain instances of `Popup`s.
  ProgressMonitor
  A class to monitor the progress of some operation.
  ProgressMonitorInputStream
  Monitors the progress of reading from some InputStream.
  Renderer
  Defines the requirements for an object responsible for "rendering" (displaying) a value.
  RepaintManager
  This class manages repaint requests, allowing the number of repaints to be minimized, for example by collapsing multiple requests into a single repaint for members of a component tree.
  RootPaneContainer
  This interface is implemented by components that have a single JRootPane child: JDialog, JFrame, JWindow, JApplet, JInternalFrame.
  RowFilter<M,I>
  `RowFilter` is used to filter out entries from the model so that they are not shown in the view.
  RowFilter.ComparisonType
  Enumeration of the possible comparison values supported by some of the default `RowFilter`s.
  RowFilter.Entry<M,I>
  An `Entry` object is passed to instances of `RowFilter`, allowing the filter to get the value of the entry's data, and thus to determine whether the entry should be shown.
  RowSorter<M>
  `RowSorter` provides the basis for sorting and filtering.
  RowSorter.SortKey
  SortKey describes the sort order for a particular column.
  Scrollable
  An interface that provides information to a scrolling container like JScrollPane.
  ScrollPaneConstants
  Constants used with the JScrollPane component.
  ScrollPaneLayout
  The layout manager used by `JScrollPane`.
  ScrollPaneLayout.UIResource
  The UI resource version of `ScrollPaneLayout`.
  SingleSelectionModel
  A model that supports at most one indexed selection.
  SizeRequirements
  For the convenience of layout managers, calculates information about the size and position of components.
  SizeSequence
  A `SizeSequence` object efficiently maintains an ordered list of sizes and corresponding positions.
  SortingFocusTraversalPolicy
  A FocusTraversalPolicy that determines traversal order by sorting the Components of a focus traversal cycle based on a given Comparator.
  SortOrder
  SortOrder is an enumeration of the possible sort orderings.
  SpinnerDateModel
  A `SpinnerModel` for sequences of `Date`s.
  SpinnerListModel
  A simple implementation of `SpinnerModel` whose values are defined by an array or a `List`.
  SpinnerModel
  A model for a potentially unbounded sequence of object values.
  SpinnerNumberModel
  A `SpinnerModel` for sequences of numbers.
  Spring
  An instance of the `Spring` class holds three properties that characterize its behavior: the minimum, preferred, and maximum values.
  SpringLayout
  A `SpringLayout` lays out the children of its associated container according to a set of constraints.
  SpringLayout.Constraints
  A `Constraints` object holds the constraints that govern the way a component's size and position change in a container controlled by a `SpringLayout`.
  SwingConstants
  A collection of constants generally used for positioning and orienting components on the screen.
  SwingContainer
  An annotation used to specify some swing-related information for the automatically generated `BeanInfo` classes.
  SwingUtilities
  A collection of utility methods for Swing.
  SwingWorker<T,V>
  An abstract class to perform lengthy GUI-interaction tasks in a background thread.
  SwingWorker.StateValue
  Values for the `state` bound property.
  Timer
  Fires one or more `ActionEvent`s at specified intervals.
  ToolTipManager
  Manages all the `ToolTips` in the system.
  TransferHandler
  This class is used to handle the transfer of a `Transferable` to and from Swing components.
  TransferHandler.DropLocation
  Represents a location where dropped data should be inserted.
  TransferHandler.TransferSupport
  This class encapsulates all relevant details of a clipboard or drag and drop transfer, and also allows for customizing aspects of the drag and drop experience.
  UIClientPropertyKey
  This interface is used only for tagging keys for client properties for `JComponent` set by UI which needs to be cleared on L&F change and serialization.
  UIDefaults
  A table of defaults for Swing components.
  UIDefaults.ActiveValue
  This class enables one to store an entry in the defaults table that's constructed each time it's looked up with one of the `getXXX(key)` methods.
  UIDefaults.LazyInputMap
  `LazyInputMap` will create a `InputMap` in its `createValue` method.
  UIDefaults.LazyValue
  This class enables one to store an entry in the defaults table that isn't constructed until the first time it's looked up with one of the `getXXX(key)` methods.
  UIDefaults.ProxyLazyValue
  This class provides an implementation of `LazyValue` which can be used to delay loading of the Class for the instance to be created.
  UIManager
  `UIManager` manages the current look and feel, the set of available look and feels, `PropertyChangeListeners` that are notified when the look and feel changes, look and feel defaults, and convenience methods for obtaining various default values.
  UIManager.LookAndFeelInfo
  Provides a little information about an installed `LookAndFeel` for the sake of configuring a menu or for initial application set up.
  UnsupportedLookAndFeelException
  An exception that indicates the requested look & feel management classes are not present on the user's system.
  ViewportLayout
  The default layout manager for `JViewport`.
  WindowConstants
  Constants used to control the window-closing operation.