8332431: NullPointerException in JTable of SwingSet2

Reviewed-by: abhiscxk, kizune

Author: prsadhuk

src/java.desktop/share/classes/javax/swing/ToolTipManager.java

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 1997, 2024, 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
@@ -265,13 +265,19 @@ void showTipWindow() {
                 toFind = new Point(screenLocation.x + preferredLocation.x,
                         screenLocation.y + preferredLocation.y);
             } else {
-                toFind = mouseEvent.getLocationOnScreen();
+                if (mouseEvent != null) {
+                    toFind = mouseEvent.getLocationOnScreen();
+                } else {
+                    toFind = screenLocation;
+                }
             }
 
             GraphicsConfiguration gc = getDrawingGC(toFind);
             if (gc == null) {
-                toFind = mouseEvent.getLocationOnScreen();
-                gc = getDrawingGC(toFind);
+                if (mouseEvent != null) {
+                    toFind = mouseEvent.getLocationOnScreen();
+                    gc = getDrawingGC(toFind);
+                }
                 if (gc == null) {
                     gc = insideComponent.getGraphicsConfiguration();
                 }
@@ -301,8 +307,12 @@ void showTipWindow() {
             location.x -= size.width;
         }
             } else {
-                location = new Point(screenLocation.x + mouseEvent.getX(),
-                        screenLocation.y + mouseEvent.getY() + 20);
+                if (mouseEvent != null) {
+                    location = new Point(screenLocation.x + mouseEvent.getX(),
+                            screenLocation.y + mouseEvent.getY() + 20);
+                } else {
+                    location = screenLocation;
+                }
         if (!leftToRight) {
             if(location.x - size.width>=0) {
                 location.x -= size.width;