--- a/jdk/src/share/classes/java/awt/event/MouseEvent.java	Thu May 21 15:04:23 2009 +0400
+++ b/jdk/src/share/classes/java/awt/event/MouseEvent.java	Fri May 22 16:09:45 2009 +0400
@@ -33,6 +33,7 @@
 import java.io.ObjectInputStream;
 import java.awt.IllegalComponentStateException;
 import java.awt.MouseInfo;
+import sun.awt.SunToolkit;
 
 /**
  * An event which indicates that a mouse action occurred in a component.
@@ -379,12 +380,25 @@
      */
     private static final long serialVersionUID = -991214153494842848L;
 
+    /**
+     * A number of buttons available on the mouse at the {@code Toolkit} machinery startup.
+     */
+    private static int cachedNumberOfButtons;
+
     static {
         /* ensure that the necessary native libraries are loaded */
         NativeLibLoader.loadLibraries();
         if (!GraphicsEnvironment.isHeadless()) {
             initIDs();
         }
+        final Toolkit tk = Toolkit.getDefaultToolkit();
+        if (tk instanceof SunToolkit) {
+            cachedNumberOfButtons = ((SunToolkit)tk).getNumberOfButtons();
+        } else {
+            //It's expected that some toolkits (Headless,
+            //whatever besides SunToolkit) could also operate.
+            cachedNumberOfButtons = 3;
+        }
     }
 
     /**
@@ -412,15 +426,6 @@
     }
 
     /**
-     * A number of buttons available on the mouse at the {@code Toolkit} machinery startup.
-     */
-    private static int cachedNumberOfButtons;
-
-    static {
-        cachedNumberOfButtons = MouseInfo.getNumberOfButtons();
-    }
-
-    /**
      * Returns the absolute horizontal x position of the event.
      * In a virtual device multi-screen environment in which the
      * desktop area could span multiple physical screen devices,
@@ -735,7 +740,6 @@
         if (button < NOBUTTON){
             throw new IllegalArgumentException("Invalid button value :" + button);
         }
-        //TODO: initialize MouseInfo.cachedNumber on toolkit creation.
         if (button > BUTTON3) {
             if (!Toolkit.getDefaultToolkit().areExtraMouseButtonsEnabled()){
                 throw new IllegalArgumentException("Extra mouse events are disabled " + button);