OpenJDK 27 · javax.swing.UIManager · APIdia, the JavaDoc alternative

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.

Specifying the look and feel

The look and feel can be specified in two distinct ways: by specifying the fully qualified name of the class for the look and feel, or by creating an instance of LookAndFeel and passing it to setLookAndFeel. The following example illustrates setting the look and feel to the system look and feel:

  UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());

The following example illustrates setting the look and feel based on class name:

  UIManager.setLookAndFeel("javax.swing.plaf.metal.MetalLookAndFeel");

Once the look and feel has been changed it is imperative to invoke updateUI on all JComponents. The method SwingUtilities#updateComponentTreeUI makes it easy to apply updateUI to a containment hierarchy. Refer to it for details. The exact behavior of not invoking updateUI after changing the look and feel is unspecified. It is very possible to receive unexpected exceptions, painting problems, or worse.

Default look and feel

The class used for the default look and feel is chosen in the following manner:

If the system property swing.defaultlaf is non-null, use its value as the default look and feel class name.
If the java.util.Properties file swing.properties exists and contains the key swing.defaultlaf, use its value as the default look and feel class name. The location that is checked for swing.properties may vary depending upon the implementation of the Java platform. Typically the swing.properties file is located in the conf subdirectory of the Java installation directory. Refer to the release notes of the implementation being used for further details.
Otherwise use the cross platform look and feel.

Defaults

UIManager manages three sets of UIDefaults. In order, they are:

Developer defaults. With few exceptions Swing does not alter the developer defaults; these are intended to be modified and used by the developer.
Look and feel defaults. The look and feel defaults are supplied by the look and feel at the time it is installed as the current look and feel (setLookAndFeel() is invoked). The look and feel defaults can be obtained using the getLookAndFeelDefaults() method.
System defaults. The system defaults are provided by Swing.

Invoking any of the various get methods results in checking each of the defaults, in order, returning the first non-null value. For example, invoking UIManager.getString("Table.foreground") results in first checking developer defaults. If the developer defaults contain a value for "Table.foreground" it is returned, otherwise the look and feel defaults are checked, followed by the system defaults.

It's important to note that getDefaults returns a custom instance of UIDefaults with this resolution logic built into it. For example, UIManager.getDefaults().getString("Table.foreground") is equivalent to UIManager.getString("Table.foreground"). Both resolve using the algorithm just described. In many places the documentation uses the word defaults to refer to the custom instance of UIDefaults with the resolution logic as previously described.

When the look and feel is changed, UIManager alters only the look and feel defaults; the developer and system defaults are not altered by the UIManager in any way.

The set of defaults a particular look and feel supports is defined and documented by that look and feel. In addition, each look and feel, or ComponentUI provided by a look and feel, may access the defaults at different times in their life cycle. Some look and feels may aggressively look up defaults, so that changing a default may not have an effect after installing the look and feel. Other look and feels may lazily access defaults so that a change to the defaults may effect an existing look and feel. Finally, other look and feels might not configure themselves from the defaults table in any way. None-the-less it is usually the case that a look and feel expects certain defaults, so that in general a ComponentUI provided by one look and feel will not work with another look and feel.

System Look and Feels

[The terms "System", "Native" and "Platform" may be used interchangeably in this context].

A System Look And Feel is intended to implement the native Look and Feel of the desktop.

There is no requirement for the standard Java Look And Feel to be the default, therefore the System Look and Feel may be the default.

A desktop may not have a consistent Look and Feel, for example if there are multiple platform-native toolkits provided to create applications for the desktop. Swing may elect any one of these to be its native Look and Feel.

Installation of the native Look and Feel may depend on platform resources being available. In the event that required resources are not available, Swing may be unable to install the System Look and Feel.

Swing's emulation of the native Look and Feel takes precedence over any component-specific indication of rendering. This means that a native Look and Feel should render in a way that is consistent with the platform, even if it contradicts component setting-specific documentation. Examples include

specified rendering of painted borders may be ignored
specified rendering of highlighting effects may be ignored
specified rendering of painted backgrounds and foregrounds may be ignored
specified rendering of selected vs unselected components may be ignored
specified rendering of enabled vs disabled components may be ignored

These are just examples. Not an exhaustive list.

These caveats must not be construed as an excuse to arbitrarily ignore these properties. They are intended to support the requirement that the platform Look and Feel be as consistent with the native rendering as is practical.

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 java.beans.XMLEncoder.

Modifier and Type	Class and Description
private static class	UIManager.LAFState This class defines the state managed by the `UIManager`.
public static class	UIManager.LookAndFeelInfo Provides a little information about an installed `LookAndFeel` for the sake of configuring a menu or for initial application set up.

Modifier and Type	Field and Description
private static final String	auxiliaryLAFsKey
private static final Object	classLock
private static final String	defaultLAFKey
private static final String	disableMnemonicKey
private static UIManager.LookAndFeelInfo[]	installedLAFs The default value of `installedLAFS` is used when no `swing.properties` file is available or if the file doesn't contain a "swing.installedlafs" property.
private static final String	installedLAFsKey
private static final UIManager.LAFState	LAF_STATE
private static final String	multiplexingLAFKey

Access	Constructor and Description
public	UIManager() Constructs a `UIManager`.

Method Summary

Modifier and Type	Method and Description
public static void	addAuxiliaryLookAndFeel(LookAndFeel the `LookAndFeel` object laf) Adds a `LookAndFeel` to the list of auxiliary look and feels.
public static void	addPropertyChangeListener(PropertyChangeListener the `PropertyChangeListener` to be added listener) Adds a `PropertyChangeListener` to the listener list.
private static void	checkProperty(Properties props, String key)
public static LookAndFeel	Returns: the built-in `LookAndFeel` object createLookAndFeel(String a `String` specifying the name of the built-in look and feel name) Creates a supported built-in Java `LookAndFeel` specified by the given `L&F; name` name.
public static Object	Returns: the `Object` get(Object an `Object` specifying the desired object key) Returns an object from the defaults.
public static Object	Returns: the `Object` get(Object an `Object` specifying the desired object key, Locale the `Locale` for which the object is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns an object from the defaults that is appropriate for the given locale.
public static LookAndFeel[]	Returns: list of auxiliary `LookAndFeel`s or `null` getAuxiliaryLookAndFeels() Returns the list of auxiliary look and feels (can be `null`).
public static boolean	Returns: the boolean value corresponding to the key getBoolean(Object an `Object` specifying the key for the desired boolean value key) Returns a boolean from the defaults which is associated with the key value.
public static boolean	Returns: the boolean value corresponding to the key getBoolean(Object an `Object` specifying the key for the desired boolean value key, Locale the `Locale` for which the boolean is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns a boolean from the defaults which is associated with the key value and the given `Locale`.
public static Border	Returns: the `Border` object getBorder(Object an `Object` specifying the border key) Returns a border from the defaults.
public static Border	Returns: the `Border` object getBorder(Object an `Object` specifying the border key, Locale the `Locale` for which the border is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns a border from the defaults that is appropriate for the given locale.
public static Color	Returns: the `Color` object getColor(Object an `Object` specifying the color key) Returns a color from the defaults.
public static Color	Returns: the `Color` object getColor(Object an `Object` specifying the color key, Locale the `Locale` for which the color is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns a color from the defaults that is appropriate for the given locale.
public static String	Returns: a string with the JLF implementation-class getCrossPlatformLookAndFeelClassName() Returns the name of the `LookAndFeel` class that implements the default cross platform look and feel -- the Java Look and Feel (JLF).
public static UIDefaults	Returns: a `UIDefaults` object containing the default values getDefaults() Returns the defaults.
public static Dimension	Returns: the `Dimension` object getDimension(Object an `Object` specifying the dimension object key) Returns a dimension from the defaults.
public static Dimension	Returns: the `Dimension` object getDimension(Object an `Object` specifying the dimension object key, Locale the `Locale` for which the object is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns a dimension from the defaults that is appropriate for the given locale.
public static Font	Returns: the `Font` object getFont(Object an `Object` specifying the font key) Returns a font from the defaults.
public static Font	Returns: the `Font` object getFont(Object an `Object` specifying the font key, Locale the `Locale` for which the font is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns a font from the defaults that is appropriate for the given locale.
public static Icon	Returns: the `Icon` object getIcon(Object an `Object` specifying the icon key) Returns an `Icon` from the defaults.
public static Icon	Returns: the `Icon` object getIcon(Object an `Object` specifying the icon key, Locale the `Locale` for which the icon is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns an `Icon` from the defaults that is appropriate for the given locale.
public static Insets	Returns: the `Insets` object getInsets(Object an `Object` specifying the `Insets` object key) Returns an `Insets` object from the defaults.
public static Insets	Returns: the `Insets` object getInsets(Object an `Object` specifying the `Insets` object key, Locale the `Locale` for which the object is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns an `Insets` object from the defaults that is appropriate for the given locale.
public static UIManager.LookAndFeelInfo[]	Returns: an array of `LookAndFeelInfo` objects getInstalledLookAndFeels() Returns an array of `LookAndFeelInfo`s representing the `LookAndFeel` implementations currently available.
public static int	Returns: the int getInt(Object an `Object` specifying the int key) Returns an integer from the defaults.
public static int	Returns: the int getInt(Object an `Object` specifying the int key, Locale the `Locale` for which the int is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns an integer from the defaults that is appropriate for the given locale.
private static UIManager.LAFState	getLAFState() Return the `LAFState` object.
public static LookAndFeel	Returns: current look and feel, or `null` getLookAndFeel() Returns the current look and feel or `null`.
public static UIDefaults	Returns: `UIDefaults` from the current look and feel getLookAndFeelDefaults() Returns the `UIDefaults` from the current look and feel, that were obtained at the time the look and feel was installed.
private static LookAndFeel	getMultiLookAndFeel() Finds the Multiplexing `LookAndFeel`.
public static PropertyChangeListener[]	Returns: all of the `PropertyChangeListener`s added or an empty array if no listeners have been added getPropertyChangeListeners() Returns an array of all the `PropertyChangeListener`s added to this UIManager with addPropertyChangeListener().
public static String	Returns: the `String` getString(Object an `Object` specifying the string key) Returns a string from the defaults.
public static String	Returns: the `String` getString(Object an `Object` specifying the string key, Locale the `Locale` for which the string is desired; refer to `UIDefaults` for details on how a `null` `Locale` is handled l) Returns a string from the defaults that is appropriate for the given locale.
pack-priv static String	Returns: the `String` getString(Object an `Object` specifying the string key, Component `Component` used to determine the locale; `null` implies the default locale as returned by `Locale.getDefault()` c) Returns a string from the defaults that is appropriate for the given locale.
public static String	Returns: the `String` of the `LookAndFeel` class getSystemLookAndFeelClassName() Returns the name of the `LookAndFeel` class that implements the native system look and feel if there is one, otherwise the name of the default cross platform `LookAndFeel` class.
public static ComponentUI	Returns: the `ComponentUI` object for `target` getUI(JComponent the `JComponent` to return the `ComponentUI` for target) Returns the appropriate `ComponentUI` implementation for `target`.
private static void	initialize()
private static void	initializeAuxiliaryLAFs(Properties swingProps)
private static void	initializeDefaultLAF(Properties swingProps) If the user has specified a default look and feel, use that.
private static void	initializeInstalledLAFs(Properties swingProps) If a `swing.properties` file exist and it has a `swing.installedlafs` property then initialize the `installedLAFs` field.
private static void	initializeSystemDefaults(Properties swingProps)
public static void	installLookAndFeel(UIManager.LookAndFeelInfo a `LookAndFeelInfo` object that names the look and feel and identifies the class that implements it info) Adds the specified look and feel to the set of available look and feels.
public static void	installLookAndFeel(String descriptive name of the look and feel name, String name of the class that implements the look and feel className) Adds the specified look and feel to the set of available look and feels.
private static boolean	isLafStateInitialized()
private static Properties	loadSwingProperties()
private static String	makeInstalledLAFKey(String laf, String attr) Return a `swing.properties` file key for the attribute of specified look and feel.
private static String	makeSwingPropertiesFilename() The location of the `swing.properties` property file is implementation-specific.
private static void	maybeInitialize()
private static void	maybeInitializeFocusPolicy(JComponent comp)
public static Object	Returns: the `Object` returned by `UIDefaults#put` put(Object an `Object` specifying the retrieval key key, Object the `Object` to store; refer to `UIDefaults` for details on how `null` is handled value) Stores an object in the developer defaults.
public static boolean	Returns: true if the `LookAndFeel` was removed from the list removeAuxiliaryLookAndFeel(LookAndFeel the `LookAndFeel` to be removed laf) Removes a `LookAndFeel` from the list of auxiliary look and feels.
public static void	removePropertyChangeListener(PropertyChangeListener the `PropertyChangeListener` to be removed listener) Removes a `PropertyChangeListener` from the listener list.
public static void	setInstalledLookAndFeels(UIManager.LookAndFeelInfo[] set of `LookAndFeelInfo` objects specifying the available look and feels infos) Sets the set of available look and feels.
public static void	setLookAndFeel(LookAndFeel `LookAndFeel` to install newLookAndFeel) Sets the current look and feel to `newLookAndFeel`.
public static void	setLookAndFeel(String a string specifying the name of the class that implements the look and feel className) Loads the `LookAndFeel` specified by the given class name, using the current thread's context class loader, and passes it to `setLookAndFeel(LookAndFeel)`.

Inherited from java.lang.Object:: clone equals finalize getClass hashCode notify notifyAll toString wait wait wait

public Class UIManager

Specifying the look and feel

Default look and feel

Defaults

System Look and Feels

Nested and Inner Type Summary

Field Summary

Constructor Summary

Method Summary