Name: jk109818 Date: 01/21/2003


FULL PRODUCT VERSION :
java version "1.4.1_01"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.1_01-b01)
Java HotSpot(TM) Client VM (build 1.4.1_01-b01, mixed mode)

FULL OPERATING SYSTEM VERSION : Microsoft Windows 2000
[Version 5.00.2195]


A DESCRIPTION OF THE PROBLEM :
Null pointer exception in ToolTipManager (version 1.4.1).

In a JPanel I am displaying a complex drawing. As the
mouse moves over the drawing different elements in the
drawing may display a tooltip. This is done by overriding
getToolTipText(MouseEvent e) in the display. getToolTipText
() returns a String when the mouse is over a tooltip-
enabled element and null otherwise. The exception below
occurs when not over a tooltip-enabled element.

java.lang.NullPointerException

at javax.swing.ToolTipManager.initiateToolTip
(ToolTipManager.java:497)

at javax.swing.ToolTipManager.mouseEntered
(ToolTipManager.java:458)

at java.awt.AWTEventMulticaster.mouseEntered
(AWTEventMulticaster.java:238)

at java.awt.AWTEventMulticaster.mouseEntered
(AWTEventMulticaster.java:237)

at java.awt.Component.processMouseEvent
(Component.java:5102)

at java.awt.Component.processEvent
(Component.java:4890)

at java.awt.Container.processEvent
(Container.java:1566)

at java.awt.Component.dispatchEventImpl
(Component.java:3598)

at java.awt.Container.dispatchEventImpl
(Container.java:1623)

at java.awt.Component.dispatchEvent
(Component.java:3439)

at java.awt.LightweightDispatcher.retargetMouseEvent
(Container.java:3450)

at
java.awt.LightweightDispatcher.trackMouseEnterExit
(Container.java:3290)

at java.awt.LightweightDispatcher.processMouseEvent
(Container.java:3147)

at java.awt.LightweightDispatcher.dispatchEvent
(Container.java:3095)

at java.awt.Container.dispatchEventImpl
(Container.java:1609)

at java.awt.Window.dispatchEventImpl
(Window.java:1585)

at java.awt.Component.dispatchEvent
(Component.java:3439)

at java.awt.EventQueue.dispatchEvent
(EventQueue.java:450)

at
java.awt.EventDispatchThread.pumpOneEventForHierarchy
(EventDispatchThread.java:197)

at
java.awt.EventDispatchThread.pumpEventsForHierarchy
(EventDispatchThread.java:150)

at java.awt.EventDispatchThread.pumpEvents
(EventDispatchThread.java:144)

at java.awt.EventDispatchThread.pumpEvents
(EventDispatchThread.java:136)

at java.awt.EventDispatchThread.run
(EventDispatchThread.java:99)


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. In a JPanel, draw several lines and a few circles.
2. Allow circles to have tooltips, for lines no tooltip
3. Moving mouse around should show this problem.

EXPECTED VERSUS ACTUAL BEHAVIOR :
No null pointer exceptions from ToolTipManager

ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.lang.NullPointerException

at javax.swing.ToolTipManager.initiateToolTip(ToolTipManager.java:497)

at javax.swing.ToolTipManager.mouseEntered(ToolTipManager.java:458)

at java.awt.AWTEventMulticaster.mouseEntered
(AWTEventMulticaster.java:238)

at java.awt.AWTEventMulticaster.mouseEntered
(AWTEventMulticaster.java:237)

at java.awt.Component.processMouseEvent(Component.java:5102)

at java.awt.Component.processEvent(Component.java:4890)

at java.awt.Container.processEvent(Container.java:1566)

at java.awt.Component.dispatchEventImpl(Component.java:3598)

at java.awt.Container.dispatchEventImpl(Container.java:1623)

at java.awt.Component.dispatchEvent(Component.java:3439)

at java.awt.LightweightDispatcher.retargetMouseEvent
(Container.java:3450)

at java.awt.LightweightDispatcher.trackMouseEnterExit
(Container.java:3290)

at java.awt.LightweightDispatcher.processMouseEvent(Container.java:3147)

at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3095)

at java.awt.Container.dispatchEventImpl(Container.java:1609)

at java.awt.Window.dispatchEventImpl(Window.java:1585)

at java.awt.Component.dispatchEvent(Component.java:3439)

at java.awt.EventQueue.dispatchEvent(EventQueue.java:450)

at java.awt.EventDispatchThread.pumpOneEventForHierarchy
(EventDispatchThread.java:197)

at java.awt.EventDispatchThread.pumpEventsForHierarchy
(EventDispatchThread.java:150)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:144)

at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:136)

at java.awt.EventDispatchThread.run(EventDispatchThread.java:99)



REPRODUCIBILITY :
This bug can be reproduced often.

---------- BEGIN SOURCE ----------
public String getToolTipText(MouseEvent e) overridden in the display.
---------- END SOURCE ----------

CUSTOMER WORKAROUND :
Returning the String "" helps, but screen still flashes
when I move mouse over it.
(Review ID: 179296)
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