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 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

Interface	Description
Action	The `Action` interface provides a useful extension to the `ActionListener` interface in cases where the same functionality may be accessed by several controls.
BoundedRangeModel	Defines the data model used by components like `Slider`s and `ProgressBar`s.
ButtonModel	State model for buttons.
CellEditor	This interface defines the methods any general editor should be able to implement.
ComboBoxEditor	The editor component used for JComboBox components.
ComboBoxModel<E>	A data model for a combo box.
DesktopManager	DesktopManager objects are owned by a JDesktopPane object.
Icon	A small fixed size picture, typically used to decorate components.
JComboBox.KeySelectionManager	The interface that defines a `KeySelectionManager`.
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.
MenuElement	Any component that can be placed into a menu should implement this interface.
MutableComboBoxModel<E>	A mutable version of `ComboBoxModel`.
Painter<T>	A painting delegate.
Renderer	Defines the requirements for an object responsible for "rendering" (displaying) a value.
RootPaneContainer	This interface is implemented by components that have a single JRootPane child: JDialog, JFrame, JWindow, JApplet, JInternalFrame.
Scrollable	An interface that provides information to a scrolling container like JScrollPane.
ScrollPaneConstants	Constants used with the JScrollPane component.
SingleSelectionModel	A model that supports at most one indexed selection.
SpinnerModel	A model for a potentially unbounded sequence of object values.
SwingConstants	A collection of constants generally used for positioning and orienting components on the screen.
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.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.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.
WindowConstants	Constants used to control the window-closing operation.

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.
ActionMap	`ActionMap` provides mappings from `Object`s (called keys or `Action` names) to `Action`s.
BorderFactory	Factory class for vending standard `Border` objects.
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.
CellRendererPane	This class is inserted in between cell renderers and the components that use them.
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.
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`.
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. 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.
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`.
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.
LookAndFeel	`LookAndFeel`, as the name implies, encapsulates a look and feel.
MenuSelectionManager	A MenuSelectionManager owns the selection in menu hierarchy.
OverlayLayout	A layout manager to arrange components over the top of each other.
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.
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.
RowFilter<M,I>	`RowFilter` is used to filter out entries from the model so that they are not shown in the view.
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.
ScrollPaneLayout	The layout manager used by `JScrollPane`.
ScrollPaneLayout.UIResource	The UI resource version of `ScrollPaneLayout`.
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.
SpinnerDateModel	A `SpinnerModel` for sequences of `Date`s.
SpinnerListModel	A simple implementation of `SpinnerModel` whose values are defined by an array or a `List`.
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`.
SwingUtilities	A collection of utility methods for Swing.
SwingWorker<T,V>	An abstract class to perform lengthy GUI-interaction tasks in a background thread.
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.
UIDefaults	A table of defaults for Swing components.
UIDefaults.LazyInputMap	`LazyInputMap` will create a `InputMap` in its `createValue` method.
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.
ViewportLayout	The default layout manager for `JViewport`.

Enum	Description
DropMode	Drop modes, used to determine the method by which a component tracks and indicates a drop location during drag and drop.
GroupLayout.Alignment	Enumeration of the possible ways `ParallelGroup` can align its children.
JTable.PrintMode	Printing modes, used in printing `JTable`s.
LayoutStyle.ComponentPlacement	`ComponentPlacement` is an enumeration of the possible ways two components can be placed relative to each other.
RowFilter.ComparisonType	Enumeration of the possible comparison values supported by some of the default `RowFilter`s.
SortOrder	SortOrder is an enumeration of the possible sort orderings.
SwingWorker.StateValue	Values for the `state` bound property.

Exception	Description
UnsupportedLookAndFeelException	An exception that indicates the requested look & feel management classes are not present on the user's system.

Annotation Type	Description
SwingContainer	An annotation used to specify some swing-related information for the automatically generated `BeanInfo` classes.

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Documentation extracted from Debian's OpenJDK Development Kit package.
Licensed under the GNU General Public License, version 2, with the Classpath Exception.
Various third party code in OpenJDK is licensed under different licenses (see Debian package).
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