在Mac上启动时，Swing GUI不会显示或显示错误

Question

I have a Java Swing project which works fine on both Windows and Ubuntu. I did not have any Macs so I could not test it; I have used the Nimbus theme as the standard for this project.

Now, recently my friend tested the same project both in Eclipse and exported jar, and it is giving errors that do not refer to any specific Java class that I have made.

It does show the GUI, but sometimes it sticks, or sometimes menus are missing.

Here is a stripped down version of errors shown while launching the GUI:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
    at com.apple.laf.AquaMenuPainter.paintMenuBarBackground(AquaMenuPainter.java:123)
    at com.apple.laf.AquaMenuUI.paintBackground(AquaMenuUI.java:57)
    at com.apple.laf.AquaMenuPainter.paintMenuItem(AquaMenuPainter.java:160)
    at com.apple.laf.AquaMenuUI.paintMenuItem(AquaMenuUI.java:35)
    at javax.swing.plaf.basic.BasicMenuItemUI.paint(BasicMenuItemUI.java:452)
    at javax.swing.plaf.basic.BasicMenuItemUI.update(BasicMenuItemUI.java:448)
    at javax.swing.JComponent.paintComponent(JComponent.java:752)
    at javax.swing.JComponent.paint(JComponent.java:1029)
    at javax.swing.JComponent.paintChildren(JComponent.java:862)
    at javax.swing.JComponent.paint(JComponent.java:1038)
    at javax.swing.JComponent.paintChildren(JComponent.java:862)
    at javax.swing.JComponent.paint(JComponent.java:1038)
    at javax.swing.JLayeredPane.paint(JLayeredPane.java:567)
    at javax.swing.JComponent.paintChildren(JComponent.java:862)
    at javax.swing.JComponent.paint(JComponent.java:1038)
    at java.awt.GraphicsCallback$PaintCallback.run(GraphicsCallback.java:34)
    at sun.awt.SunGraphicsCallback.runOneComponent(SunGraphicsCallback.java:60)
    at sun.awt.SunGraphicsCallback.runComponents(SunGraphicsCallback.java:97)  

Could you tell me what could be the problem, or is there any specific Look and Feel theme I should be using on Mac? Is Nimbus not supported on Mac and if so then what should I use?

Answer 1

I wouldn't touch the theme in OS X, it is awesome automatically :D

Just make sure you don't change the theme when you are on Mac.

String osName = System.getProperty("os.name").toLowerCase();
if (!osName.contains("mac")) // if not on mac
{
   // set nimbus
}
// otherwise, do nothing. It goes automatically to Aqua.