NPE at javax.swing.ToolTipManager.initiateToolTip(ToolTipManager.java:478)

[pmouawad]

Describe the bug

Using JMeter latest nightly build with Darklaf latest release I get many NPE with below stacktrace:
Note I had reported a similar bug:

• NPE in javax.swing.ToolTipManager.initiateToolTip(ToolTipManager.java:478) ~[?:1.8.0_201] #183

java.lang.NullPointerException: null at javax.swing.ToolTipManager.initiateToolTip(ToolTipManager.java:478) ~[?:1.8.0_161] at javax.swing.ToolTipManager.mouseEntered(ToolTipManager.java:435) ~[?:1.8.0_161] at com.github.weisj.darklaf.ui.tooltip.DarkToolTipUI$2.mouseEntered(DarkToolTipUI.java:79) ~[darklaf-core-2.5.3.jar:2.5.3] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:300) ~[?:1.8.0_161] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:299) ~[?:1.8.0_161] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:299) ~[?:1.8.0_161] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:299) ~[?:1.8.0_161] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:299) ~[?:1.8.0_161] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:299) ~[?:1.8.0_161] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:299) ~[?:1.8.0_161] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:299) ~[?:1.8.0_161] at java.awt.AWTEventMulticaster.mouseEntered(AWTEventMulticaster.java:299) ~[?:1.8.0_161] at java.awt.Component.processMouseEvent(Component.java:6542) ~[?:1.8.0_161] at javax.swing.JComponent.processMouseEvent(JComponent.java:3324) ~[?:1.8.0_161] at java.awt.Component.processEvent(Component.java:6298) ~[?:1.8.0_161] at java.awt.Container.processEvent(Container.java:2237) ~[?:1.8.0_161] at java.awt.Component.dispatchEventImpl(Component.java:4889) ~[?:1.8.0_161] at java.awt.Container.dispatchEventImpl(Container.java:2295) ~[?:1.8.0_161] at java.awt.Component.dispatchEvent(Component.java:4711) ~[?:1.8.0_161] at java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4889) ~[?:1.8.0_161] at java.awt.LightweightDispatcher.retargetMouseEnterExit(Container.java:4677) ~[?:1.8.0_161] at java.awt.LightweightDispatcher.trackMouseEnterExit(Container.java:4655) ~[?:1.8.0_161] at java.awt.LightweightDispatcher.processMouseEvent(Container.java:4506) ~[?:1.8.0_161] at java.awt.LightweightDispatcher.dispatchEvent(Container.java:4467) ~[?:1.8.0_161] at java.awt.Container.dispatchEventImpl(Container.java:2281) ~[?:1.8.0_161] at java.awt.Window.dispatchEventImpl(Window.java:2746) ~[?:1.8.0_161] at java.awt.Component.dispatchEvent(Component.java:4711) ~[?:1.8.0_161] at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758) ~[?:1.8.0_161] at java.awt.EventQueue.access$500(EventQueue.java:97) ~[?:1.8.0_161] at java.awt.EventQueue$3.run(EventQueue.java:709) ~[?:1.8.0_161] at java.awt.EventQueue$3.run(EventQueue.java:703) ~[?:1.8.0_161] at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_161] at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80) ~[?:1.8.0_161] at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:90) ~[?:1.8.0_161] at java.awt.EventQueue$4.run(EventQueue.java:731) ~[?:1.8.0_161] at java.awt.EventQueue$4.run(EventQueue.java:729) ~[?:1.8.0_161] at java.security.AccessController.doPrivileged(Native Method) ~[?:1.8.0_161] at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:80) ~[?:1.8.0_161] at java.awt.EventQueue.dispatchEvent(EventQueue.java:728) ~[?:1.8.0_161] at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201) [?:1.8.0_161] at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116) [?:1.8.0_161] at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105) [?:1.8.0_161] at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101) [?:1.8.0_161] at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93) [?:1.8.0_161] at java.awt.EventDispatchThread.run(EventDispatchThread.java:82) [?:1.8.0_161]

To Reproduce

I cannot tell exactly when it starts to happen.
No plugin used, just core jmeter.

Screenshots

I see no impact unless this one is related:

I notice that after certain time , the left and right key instead of closing / opening a leaf start to select previous / next node of JTree.

Additional Information:

• OS: Mac OSX
• OS Version: 10.11.6
• JDK 1.8.0_161
• Darklaf Version: 2.5.3

Additional context

This does not happen with System LAF.

[weisJ]

Is this still for the project tree?

[ubikloadpack]

Yes

[pmouawad]

Hello @weisJ ,
Thinking more about it, there is also the View Results Tree I was using which contains a JTree.

I don't know which one was leading to the NPE.
Regards

[pmouawad]

Hello @weisJ ,
I see the was a change in JMeter that might explain reapparition of NPE:

You have made a PR:

• Prevent NPE in ToolTipManager apache/jmeter#621

But this introduced this bug::

• https://bz.apache.org/bugzilla/show_bug.cgi?id=64963

Which was fixed by removing what you had put in your PR:

• apache/jmeter@b8c35f1#diff-c29d87213ad842384446cdab147eb08eec0e24362862aec545e541a957f4e2d7

FI: @FSchumacher

[FSchumacher]

So maybe, we (JMeter) should switch back to returning an empty tooltip? It seems, there is no good way to handle it.

[weisJ]

Which was fixed by removing what you had put in your PR:

• apache/jmeter@b8c35f1#diff-c29d87213ad842384446cdab147eb08eec0e24362862aec545e541a957f4e2d7

This definitely solves the question for the cause of the issue.

So maybe, we (JMeter) should switch back to returning an empty tooltip? It seems, there is no good way to handle it.

The problem here really is that the jdk prior to version 9 has an conflicting implementation regarding tooltips in JTree. I think the easiest solution would be to either return null or "" depending on whether darklaf or a jdk laf is used.

[pmouawad]

Thanks @weisJ for the idea.
Did it like this.