https://openjdk.java.net/ 
/*
 * Copyright (c) 2005, 2013, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * questions.
 */

package java.awt;

import java.util.Vector;
import java.awt.peer.SystemTrayPeer;
import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import sun.awt.AppContext;
import sun.awt.SunToolkit;
import sun.awt.HeadlessToolkit;
import sun.security.util.SecurityConstants;
import sun.awt.AWTAccessor;


The SystemTray class represents the system tray for a
desktop.  On Microsoft Windows it is referred to as the "Taskbar
Status Area", on Gnome it is referred to as the "Notification
Area", on KDE it is referred to as the "System Tray".  The system
tray is shared by all applications running on the desktop.

 On some platforms the system tray may not be present or may not be supported, in this case getSystemTray() throws UnsupportedOperationException. To detect whether the system tray is supported, use isSupported. 
The SystemTray may contain one or more TrayIcons, which are added to the tray using the add method, and removed when no longer needed, using the remove. TrayIcon consists of an image, a popup menu and a set of associated listeners. Please see the TrayIcon class for details. 
Every Java application has a single SystemTray
instance that allows the app to interface with the system tray of
the desktop while the app is running.  The SystemTray instance can be obtained from the getSystemTray method. An application may not create its own instance of SystemTray.

The following code snippet demonstrates how to access
and customize the system tray:

 TrayIcon trayIcon = null; if (SystemTray.isSupported()) { // get the SystemTray instance SystemTray tray = SystemTray.getSystemTray; // load an image Image image = Toolkit.getDefaultToolkit().getImage(...); // create a action listener to listen for default action executed on the tray icon ActionListener listener = new ActionListener() { public void actionPerformed(ActionEvent e) { // execute default action of the application // ... } }; // create a popup menu PopupMenu popup = new PopupMenu(); // create menu item for the default action MenuItem defaultItem = new MenuItem(...); defaultItem.addActionListener(listener); popup.add(defaultItem); /// ... add other items // construct a TrayIcon trayIcon = new TrayIcon(image, "Tray Demo", popup); // set the TrayIcon properties trayIcon.addActionListener(listener); // ... // add the tray image try { tray.add(trayIcon); } catch (AWTException e) { System.err.println(e); } // ... } else { // disable tray option in your application or // perform other actions ... } // ... // some time later // the application state has changed - update the image if (trayIcon != null) { trayIcon.setImage(updatedImage); } // ... 



Author:Bino George, Denis Mikhalkin, Sharon Zakhour, Anton Tarasov
See Also:
Since:1.6
/**
 * The <code>SystemTray</code> class represents the system tray for a
 * desktop.  On Microsoft Windows it is referred to as the "Taskbar
 * Status Area", on Gnome it is referred to as the "Notification
 * Area", on KDE it is referred to as the "System Tray".  The system
 * tray is shared by all applications running on the desktop.
 *
 * <p> On some platforms the system tray may not be present or may not
 * be supported, in this case {@link SystemTray#getSystemTray()}
 * throws {@link UnsupportedOperationException}.  To detect whether the
 * system tray is supported, use {@link SystemTray#isSupported}.
 *
 * <p>The <code>SystemTray</code> may contain one or more {@link
 * TrayIcon TrayIcons}, which are added to the tray using the {@link
 * #add} method, and removed when no longer needed, using the
 * {@link #remove}.  <code>TrayIcon</code> consists of an
 * image, a popup menu and a set of associated listeners.  Please see
 * the {@link TrayIcon} class for details.
 *
 * <p>Every Java application has a single <code>SystemTray</code>
 * instance that allows the app to interface with the system tray of
 * the desktop while the app is running.  The <code>SystemTray</code>
 * instance can be obtained from the {@link #getSystemTray} method.
 * An application may not create its own instance of
 * <code>SystemTray</code>.
 *
 * <p>The following code snippet demonstrates how to access
 * and customize the system tray:
 * <pre>
 * <code>
 *     {@link TrayIcon} trayIcon = null;
 *     if (SystemTray.isSupported()) {
 *         // get the SystemTray instance
 *         SystemTray tray = SystemTray.{@link #getSystemTray};
 *         // load an image
 *         {@link java.awt.Image} image = {@link java.awt.Toolkit#getImage(String) Toolkit.getDefaultToolkit().getImage}(...);
 *         // create a action listener to listen for default action executed on the tray icon
 *         {@link java.awt.event.ActionListener} listener = new {@link java.awt.event.ActionListener ActionListener}() {
 *             public void {@link java.awt.event.ActionListener#actionPerformed actionPerformed}({@link java.awt.event.ActionEvent} e) {
 *                 // execute default action of the application
 *                 // ...
 *             }
 *         };
 *         // create a popup menu
 *         {@link java.awt.PopupMenu} popup = new {@link java.awt.PopupMenu#PopupMenu PopupMenu}();
 *         // create menu item for the default action
 *         MenuItem defaultItem = new MenuItem(...);
 *         defaultItem.addActionListener(listener);
 *         popup.add(defaultItem);
 *         /// ... add other items
 *         // construct a TrayIcon
 *         trayIcon = new {@link TrayIcon#TrayIcon(java.awt.Image, String, java.awt.PopupMenu) TrayIcon}(image, "Tray Demo", popup);
 *         // set the TrayIcon properties
 *         trayIcon.{@link TrayIcon#addActionListener(java.awt.event.ActionListener) addActionListener}(listener);
 *         // ...
 *         // add the tray image
 *         try {
 *             tray.{@link SystemTray#add(TrayIcon) add}(trayIcon);
 *         } catch (AWTException e) {
 *             System.err.println(e);
 *         }
 *         // ...
 *     } else {
 *         // disable tray option in your application or
 *         // perform other actions
 *         ...
 *     }
 *     // ...
 *     // some time later
 *     // the application state has changed - update the image
 *     if (trayIcon != null) {
 *         trayIcon.{@link TrayIcon#setImage(java.awt.Image) setImage}(updatedImage);
 *     }
 *     // ...
 * </code>
 * </pre>
 *
 * @since 1.6
 * @see TrayIcon
 *
 * @author Bino George
 * @author Denis Mikhalkin
 * @author Sharon Zakhour
 * @author Anton Tarasov
 */
public class SystemTray {
    private static SystemTray systemTray;
    private int currentIconID = 0; // each TrayIcon added gets a unique ID

    transient private SystemTrayPeer peer;

    private static final TrayIcon[] EMPTY_TRAY_ARRAY = new TrayIcon[0];

    static {
        AWTAccessor.setSystemTrayAccessor(
            new AWTAccessor.SystemTrayAccessor() {
                public void firePropertyChange(SystemTray tray,
                                               String propertyName,
                                               Object oldValue,
                                               Object newValue) {
                    tray.firePropertyChange(propertyName, oldValue, newValue);
                }
            });
    }

    
Private SystemTray constructor.

/**
     * Private <code>SystemTray</code> constructor.
     *
     */
    private SystemTray() {
        addNotify();
    }

    
Gets the SystemTray instance that represents the desktop's tray area. This always returns the same instance per application. On some platforms the system tray may not be supported. You may use the isSupported method to check if the system tray is supported. 
If a SecurityManager is installed, the AWTPermission accessSystemTray must be granted in order to get the SystemTray instance. Otherwise this method will throw a SecurityException. 
Throws:
See Also:
Returns:the SystemTray instance that represents
the desktop's tray area
/**
     * Gets the <code>SystemTray</code> instance that represents the
     * desktop's tray area.  This always returns the same instance per
     * application.  On some platforms the system tray may not be
     * supported.  You may use the {@link #isSupported} method to
     * check if the system tray is supported.
     *
     * <p>If a SecurityManager is installed, the AWTPermission
     * {@code accessSystemTray} must be granted in order to get the
     * {@code SystemTray} instance. Otherwise this method will throw a
     * SecurityException.
     *
     * @return the <code>SystemTray</code> instance that represents
     * the desktop's tray area
     * @throws UnsupportedOperationException if the system tray isn't
     * supported by the current platform
     * @throws HeadlessException if
     * <code>GraphicsEnvironment.isHeadless()</code> returns <code>true</code>
     * @throws SecurityException if {@code accessSystemTray} permission
     * is not granted
     * @see #add(TrayIcon)
     * @see TrayIcon
     * @see #isSupported
     * @see SecurityManager#checkPermission
     * @see AWTPermission
     */
    public static SystemTray getSystemTray() {
        checkSystemTrayAllowed();
        if (GraphicsEnvironment.isHeadless()) {
            throw new HeadlessException();
        }

        initializeSystemTrayIfNeeded();

        if (!isSupported()) {
            throw new UnsupportedOperationException(
                "The system tray is not supported on the current platform.");
        }

        return systemTray;
    }

    
Returns whether the system tray is supported on the current platform. In addition to displaying the tray icon, minimal system tray support includes either a popup menu (see TrayIcon.setPopupMenu(PopupMenu)) or an action event (see TrayIcon.addActionListener(ActionListener)). 
Developers should not assume that all of the system tray functionality is supported. To guarantee that the tray icon's default action is always accessible, add the default action to both the action listener and the popup menu. See the example for an example of how to do this. 
Note: When implementing SystemTray and
TrayIcon it is strongly recommended that
you assign different gestures to the popup menu and an action
event.  Overloading a gesture for both purposes is confusing
and may prevent the user from accessing one or the other.

See Also:
Returns:false if no system tray access is supported; this
method returns true if the minimal system tray access is
supported but does not guarantee that all system tray
functionality is supported for the current platform
/**
     * Returns whether the system tray is supported on the current
     * platform.  In addition to displaying the tray icon, minimal
     * system tray support includes either a popup menu (see {@link
     * TrayIcon#setPopupMenu(PopupMenu)}) or an action event (see
     * {@link TrayIcon#addActionListener(ActionListener)}).
     *
     * <p>Developers should not assume that all of the system tray
     * functionality is supported.  To guarantee that the tray icon's
     * default action is always accessible, add the default action to
     * both the action listener and the popup menu.  See the {@link
     * SystemTray example} for an example of how to do this.
     *
     * <p><b>Note</b>: When implementing <code>SystemTray</code> and
     * <code>TrayIcon</code> it is <em>strongly recommended</em> that
     * you assign different gestures to the popup menu and an action
     * event.  Overloading a gesture for both purposes is confusing
     * and may prevent the user from accessing one or the other.
     *
     * @see #getSystemTray
     * @return <code>false</code> if no system tray access is supported; this
     * method returns <code>true</code> if the minimal system tray access is
     * supported but does not guarantee that all system tray
     * functionality is supported for the current platform
     */
    public static boolean isSupported() {
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        if (toolkit instanceof SunToolkit) {
            // connecting tray to native resource
            initializeSystemTrayIfNeeded();
            return ((SunToolkit)toolkit).isTraySupported();
        } else if (toolkit instanceof HeadlessToolkit) {
            // skip initialization as the init routine
            // throws HeadlessException
            return ((HeadlessToolkit)toolkit).isTraySupported();
        } else {
            return false;
        }
    }

    
Adds a TrayIcon to the SystemTray.
The tray icon becomes visible in the system tray once it is
added.  The order in which icons are displayed in a tray is not
specified - it is platform and implementation-dependent.

 All icons added by the application are automatically
removed from the SystemTray upon application exit
and also when the desktop system tray becomes unavailable.

Params:
  • trayIcon – the TrayIcon to be added
Throws:
See Also:
/**
     * Adds a <code>TrayIcon</code> to the <code>SystemTray</code>.
     * The tray icon becomes visible in the system tray once it is
     * added.  The order in which icons are displayed in a tray is not
     * specified - it is platform and implementation-dependent.
     *
     * <p> All icons added by the application are automatically
     * removed from the <code>SystemTray</code> upon application exit
     * and also when the desktop system tray becomes unavailable.
     *
     * @param trayIcon the <code>TrayIcon</code> to be added
     * @throws NullPointerException if <code>trayIcon</code> is
     * <code>null</code>
     * @throws IllegalArgumentException if the same instance of
     * a <code>TrayIcon</code> is added more than once
     * @throws AWTException if the desktop system tray is missing
     * @see #remove(TrayIcon)
     * @see #getSystemTray
     * @see TrayIcon
     * @see java.awt.Image
     */
    public void add(TrayIcon trayIcon) throws AWTException {
        if (trayIcon == null) {
            throw new NullPointerException("adding null TrayIcon");
        }
        TrayIcon[] oldArray = null, newArray = null;
        Vector<TrayIcon> icons = null;
        synchronized (this) {
            oldArray = systemTray.getTrayIcons();
            icons = (Vector<TrayIcon>)AppContext.getAppContext().get(TrayIcon.class);
            if (icons == null) {
                icons = new Vector<TrayIcon>(3);
                AppContext.getAppContext().put(TrayIcon.class, icons);

            } else if (icons.contains(trayIcon)) {
                throw new IllegalArgumentException("adding TrayIcon that is already added");
            }
            icons.add(trayIcon);
            newArray = systemTray.getTrayIcons();

            trayIcon.setID(++currentIconID);
        }
        try {
            trayIcon.addNotify();
        } catch (AWTException e) {
            icons.remove(trayIcon);
            throw e;
        }
        firePropertyChange("trayIcons", oldArray, newArray);
    }

    
Removes the specified TrayIcon from the
SystemTray.

 All icons added by the application are automatically
removed from the SystemTray upon application exit
and also when the desktop system tray becomes unavailable.

 If trayIcon is null or was not
added to the system tray, no exception is thrown and no action
is performed.

Params:
  • trayIcon – the TrayIcon to be removed
See Also:
/**
     * Removes the specified <code>TrayIcon</code> from the
     * <code>SystemTray</code>.
     *
     * <p> All icons added by the application are automatically
     * removed from the <code>SystemTray</code> upon application exit
     * and also when the desktop system tray becomes unavailable.
     *
     * <p> If <code>trayIcon</code> is <code>null</code> or was not
     * added to the system tray, no exception is thrown and no action
     * is performed.
     *
     * @param trayIcon the <code>TrayIcon</code> to be removed
     * @see #add(TrayIcon)
     * @see TrayIcon
     */
    public void remove(TrayIcon trayIcon) {
        if (trayIcon == null) {
            return;
        }
        TrayIcon[] oldArray = null, newArray = null;
        synchronized (this) {
            oldArray = systemTray.getTrayIcons();
            Vector<TrayIcon> icons = (Vector<TrayIcon>)AppContext.getAppContext().get(TrayIcon.class);
            // TrayIcon with no peer is not contained in the array.
            if (icons == null || !icons.remove(trayIcon)) {
                return;
            }
            trayIcon.removeNotify();
            newArray = systemTray.getTrayIcons();
        }
        firePropertyChange("trayIcons", oldArray, newArray);
    }

    
Returns an array of all icons added to the tray by this
application.  You can't access the icons added by another
application.  Some browsers partition applets in different
code bases into separate contexts, and establish walls between
these contexts.  In such a scenario, only the tray icons added
from this context will be returned.

 The returned array is a copy of the actual array and may be
modified in any way without affecting the system tray.  To
remove a TrayIcon from the
SystemTray, use the remove(TrayIcon) method. 
See Also:
Returns:an array of all tray icons added to this tray, or an
empty array if none has been added
/**
     * Returns an array of all icons added to the tray by this
     * application.  You can't access the icons added by another
     * application.  Some browsers partition applets in different
     * code bases into separate contexts, and establish walls between
     * these contexts.  In such a scenario, only the tray icons added
     * from this context will be returned.
     *
     * <p> The returned array is a copy of the actual array and may be
     * modified in any way without affecting the system tray.  To
     * remove a <code>TrayIcon</code> from the
     * <code>SystemTray</code>, use the {@link
     * #remove(TrayIcon)} method.
     *
     * @return an array of all tray icons added to this tray, or an
     * empty array if none has been added
     * @see #add(TrayIcon)
     * @see TrayIcon
     */
    public TrayIcon[] getTrayIcons() {
        Vector<TrayIcon> icons = (Vector<TrayIcon>)AppContext.getAppContext().get(TrayIcon.class);
        if (icons != null) {
            return (TrayIcon[])icons.toArray(new TrayIcon[icons.size()]);
        }
        return EMPTY_TRAY_ARRAY;
    }

    
Returns the size, in pixels, of the space that a tray icon will occupy in the system tray. Developers may use this methods to acquire the preferred size for the image property of a tray icon before it is created. For convenience, there is a similar method TrayIcon.getSize in the TrayIcon class.

See Also:
Returns:the default size of a tray icon, in pixels
/**
     * Returns the size, in pixels, of the space that a tray icon will
     * occupy in the system tray.  Developers may use this methods to
     * acquire the preferred size for the image property of a tray icon
     * before it is created.  For convenience, there is a similar
     * method {@link TrayIcon#getSize} in the <code>TrayIcon</code> class.
     *
     * @return the default size of a tray icon, in pixels
     * @see TrayIcon#setImageAutoSize(boolean)
     * @see java.awt.Image
     * @see TrayIcon#getSize()
     */
    public Dimension getTrayIconSize() {
        return peer.getTrayIconSize();
    }

    
Adds a PropertyChangeListener to the list of listeners for the specific property. The following properties are currently supported: 



   Property
   Description




   trayIcons
   The SystemTray's array of TrayIcon objects. The array is accessed via the getTrayIcons method.

       This property is changed when a tray icon is added to (or removed
       from) the system tray.
 For example, this property is changed
       when the system tray becomes unavailable on the desktop

       and the tray icons are automatically removed.		




   systemTray
   This property contains SystemTray instance when the system tray is available or null otherwise.
 This property is changed
       when the system tray becomes available or unavailable on the desktop.
 The property is accessed by the getSystemTray method.		





 The listener listens to property changes only in this context. 
 If listener is null, no exception is thrown and no action is performed. 
Params:
  • propertyName – the specified property
  • listener – the property change listener to be added
See Also:
/**
     * Adds a {@code PropertyChangeListener} to the list of listeners for the
     * specific property. The following properties are currently supported:
     *
     * <table border=1 summary="SystemTray properties">
     * <tr>
     *    <th>Property</th>
     *    <th>Description</th>
     * </tr>
     * <tr>
     *    <td>{@code trayIcons}</td>
     *    <td>The {@code SystemTray}'s array of {@code TrayIcon} objects.
     *        The array is accessed via the {@link #getTrayIcons} method.<br>
     *        This property is changed when a tray icon is added to (or removed
     *        from) the system tray.<br> For example, this property is changed
     *        when the system tray becomes unavailable on the desktop<br>
     *        and the tray icons are automatically removed.</td>
     * </tr>
     * <tr>
     *    <td>{@code systemTray}</td>
     *    <td>This property contains {@code SystemTray} instance when the system tray
     *        is available or <code>null</code> otherwise.<br> This property is changed
     *        when the system tray becomes available or unavailable on the desktop.<br>
     *        The property is accessed by the {@link #getSystemTray} method.</td>
     * </tr>
     * </table>
     * <p>
     * The {@code listener} listens to property changes only in this context.
     * <p>
     * If {@code listener} is {@code null}, no exception is thrown
     * and no action is performed.
     *
     * @param propertyName the specified property
     * @param listener the property change listener to be added
     *
     * @see #removePropertyChangeListener
     * @see #getPropertyChangeListeners
     */
    public synchronized void addPropertyChangeListener(String propertyName,
                                                       PropertyChangeListener listener)
    {
        if (listener == null) {
            return;
        }
        getCurrentChangeSupport().addPropertyChangeListener(propertyName, listener);
    }

    
Removes a PropertyChangeListener from the listener list for a specific property. 
 The PropertyChangeListener must be from this context. 
 If propertyName or listener is null or invalid, no exception is thrown and no action is taken. 
Params:
  • propertyName – the specified property
  • listener – the PropertyChangeListener to be removed
See Also:
/**
     * Removes a {@code PropertyChangeListener} from the listener list
     * for a specific property.
     * <p>
     * The {@code PropertyChangeListener} must be from this context.
     * <p>
     * If {@code propertyName} or {@code listener} is {@code null} or invalid,
     * no exception is thrown and no action is taken.
     *
     * @param propertyName the specified property
     * @param listener the PropertyChangeListener to be removed
     *
     * @see #addPropertyChangeListener
     * @see #getPropertyChangeListeners
     */
    public synchronized void removePropertyChangeListener(String propertyName,
                                                          PropertyChangeListener listener)
    {
        if (listener == null) {
            return;
        }
        getCurrentChangeSupport().removePropertyChangeListener(propertyName, listener);
    }

    
Returns an array of all the listeners that have been associated
with the named property.


Only the listeners in this context are returned.

Params:
  • propertyName – the specified property
See Also:
Returns:all of the PropertyChangeListeners associated with the named property; if no such listeners have been added or if propertyName is null or invalid, an empty array is returned
/**
     * Returns an array of all the listeners that have been associated
     * with the named property.
     * <p>
     * Only the listeners in this context are returned.
     *
     * @param propertyName the specified property
     * @return all of the {@code PropertyChangeListener}s associated with
     *         the named property; if no such listeners have been added or
     *         if {@code propertyName} is {@code null} or invalid, an empty
     *         array is returned
     *
     * @see #addPropertyChangeListener
     * @see #removePropertyChangeListener
     */
    public synchronized PropertyChangeListener[] getPropertyChangeListeners(String propertyName) {
        return getCurrentChangeSupport().getPropertyChangeListeners(propertyName);
    }


    // ***************************************************************
    // ***************************************************************


    
Support for reporting bound property changes for Object properties.
This method can be called when a bound property has changed and it will
send the appropriate PropertyChangeEvent to any registered
PropertyChangeListeners.

Params:
  • propertyName – the property whose value has changed
  • oldValue – the property's previous value
  • newValue – the property's new value
/**
     * Support for reporting bound property changes for Object properties.
     * This method can be called when a bound property has changed and it will
     * send the appropriate PropertyChangeEvent to any registered
     * PropertyChangeListeners.
     *
     * @param propertyName the property whose value has changed
     * @param oldValue the property's previous value
     * @param newValue the property's new value
     */
    private void firePropertyChange(String propertyName,
                                    Object oldValue, Object newValue)
    {
        if (oldValue != null && newValue != null && oldValue.equals(newValue)) {
            return;
        }
        getCurrentChangeSupport().firePropertyChange(propertyName, oldValue, newValue);
    }

    
Returns the current PropertyChangeSupport instance for the
calling thread's context.

Returns:this thread's context's PropertyChangeSupport
/**
     * Returns the current PropertyChangeSupport instance for the
     * calling thread's context.
     *
     * @return this thread's context's PropertyChangeSupport
     */
    private synchronized PropertyChangeSupport getCurrentChangeSupport() {
        PropertyChangeSupport changeSupport =
            (PropertyChangeSupport)AppContext.getAppContext().get(SystemTray.class);

        if (changeSupport == null) {
            changeSupport = new PropertyChangeSupport(this);
            AppContext.getAppContext().put(SystemTray.class, changeSupport);
        }
        return changeSupport;
    }

    synchronized void addNotify() {
        if (peer == null) {
            Toolkit toolkit = Toolkit.getDefaultToolkit();
            if (toolkit instanceof SunToolkit) {
                peer = ((SunToolkit)Toolkit.getDefaultToolkit()).createSystemTray(this);
            } else if (toolkit instanceof HeadlessToolkit) {
                peer = ((HeadlessToolkit)Toolkit.getDefaultToolkit()).createSystemTray(this);
            }
        }
    }

    static void checkSystemTrayAllowed() {
        SecurityManager security = System.getSecurityManager();
        if (security != null) {
            security.checkPermission(SecurityConstants.AWT.ACCESS_SYSTEM_TRAY_PERMISSION);
        }
    }

    private static void initializeSystemTrayIfNeeded() {
        synchronized (SystemTray.class) {
            if (systemTray == null) {
                systemTray = new SystemTray();
            }
        }
    }
}