NPE in FastGradientPainter

[pentavalle]

Hi, i have a problem with a JideTabbedPane.
Same app on windowx xp runs fine, but on ubuntu 8.10 give this error:

Code: Select all

Exception occurred during event dispatching:
java.lang.NullPointerException
   at com.jidesoft.swing.FastGradientPainter.createGradientTile(Unknown Source)
   at com.jidesoft.swing.FastGradientPainter.drawGradient(Unknown Source)
   at com.jidesoft.swing.JideSwingUtilities.fillGradient(Unknown Source)
   at com.jidesoft.plaf.eclipse.Eclipse3xJideTabbedPaneUI.paintTabBackground(Unknown Source)
   at com.jidesoft.plaf.basic.BasicJideTabbedPaneUI.paintTab(Unknown Source)
   at com.jidesoft.plaf.eclipse.Eclipse3xJideTabbedPaneUI.paintTabArea(Unknown Source)
   at com.jidesoft.plaf.basic.BasicJideTabbedPaneUI$ScrollableTabPanel.paintComponent(Unknown Source)
   at javax.swing.JComponent.paint(JComponent.java:1027)


I use JIDE Common 2.4.8.
What's wrong with that?

[JIDE Support]

Could you please get the source code from JIDE Common Layer at https://jide-oss.dev.java.net and use it so that we can see the exact line # in the stack trace?

[pentavalle]

Uhm, i discovered that this exception disappear if i use XERTO_STYLE. previously i used ECLIPSE3X_STYLE.
Must i compile JIDE Common Layer manually to use it with debug informations?

[JIDE Support]

Probably a color UI resource is null under eclipse style. You could use the pre-compile jar under documents and files section on that site.

[pentavalle]

FastGradientPainter:77
info.startcolor = null

This is the cause of the NPE. Hope this will help you.

[JIDE Support]

I don't have an ubuntu to test at the moment. On Window, even I set the L&F to Metal, it still runs fine. Could you please do me a favor and debug into Eclipse3xJideTabbedPaneUI.paintTabBackground method and let me know what is null? There are two background colors.

Thanks,

[pentavalle]

background1 = null

[JIDE Support]

That's weird. It sounds like UIDefault "activeCaption" is null in the L&F you are using. Which L&F are you using?

Thanks,

[pentavalle]

GTK+, system default on ubuntu (Gnome based)

[JIDE Support]

We have GTKInitializer which set the "activeCaption" UIDefault. You can see it in LookAndFeelFactory. Are you on the latest version?

Thanks,

[pentavalle]

I agree, in GTKInitializer "activeCaption" is correctly setted... I have no ideas, tell me if i can be useful with other tests.
I am using 2.4.8 version and java 6u10.

[JIDE Support]

Could you please debug to see if GTKInitializer is called, then put a bp at paintTabBackground and inspect UIDefault.get("activeCaption")? I can only guess GTKInitializer is not called for some reason. Otherwrise it should work.

Thanks,

[pentavalle]

I can confirm you that GTKInitializer is called. I didn't understand where to put UIDefault.get("activeCaption"), so i put a bp in Eclipse3xJideTabbedPaneUI.paintTabBackground and the expression UIDefaultsLookup.getColor("activeCaption") gave me a ColorUIResource with r=250, g=209, b=132.

[JIDE Support]

You could debug the paintTabBackground method line by line and find out why the background1 is null. It is surprise because background1 is assigned from UIDefaultsLookup.getColor("DockableFrame.activeTitleBackground") which in turned assigned from UIDefault.get("activeCaption"). If UIDefault.get("activeCaption") is not null, background1 shouldn't be null either.

Thanks,

[pentavalle]

I am not sure, but it seems that "DockableFrame.activeTitleBackground" is setted in 2 classes: EclipseWindowsUtils and EclipseMetalUtils, but none of them is called...

[JIDE Support]

That's weird. I looked at LookAndFeelFactory.java (btw, the source code for it is available on https://jide-oss.dev.java.net) and didn't see a reason EclipseMetalUtils is not used even for Ubuntu (the installJideExtension is the method that calls this). GTK L&F is considered if you look at the source code of LookAndFeelFactory.java:700 and the next switch statement will call EclipseMetalUtils. It would be helpful to see a test case that I can run on Ubuntu to reproduce the exception.

Thanks,