The Java Kernel build is inconsistently giving errors such as:

Creating javax_swing_core...
Exec: "C:\nightly.1.6.0_04\tmp\kernel\j2re-image-copy\bin\java" -verbose -Dkerne
l.download.url=internal-resource/ -Dkernel.background.download=false -classpath
SplitJRE.jar;"C:/nightly.1.6.0_04/tmp/kernel/j2re-image-copy"/lib/plugin.jar;"C:
/nightly.1.6.0_04/tmp/kernel/j2re-image-copy"/lib/deploy.jar sun.kernel.SwingTes
t in working directory: C:\nightly.1.6.0_04\tmp\kernel\SplitJRE.jar
Exception in thread "main" java.lang.IllegalArgumentException: null delegate ico
n argument
       at javax.swing.plaf.IconUIResource.<init>(IconUIResource.java:49)
       at javax.swing.plaf.metal.OceanTheme$COIcon.<init>(OceanTheme.java:68)
       at javax.swing.plaf.metal.OceanTheme$6.createValue(OceanTheme.java:276)
       at javax.swing.UIDefaults.getFromHashtable(UIDefaults.java:199)
       at javax.swing.UIDefaults.get(UIDefaults.java:144)
       at javax.swing.MultiUIDefaults.get(MultiUIDefaults.java:44)
       at javax.swing.UIManager.get(UIManager.java:952)
       at javax.swing.plaf.basic.BasicTreeUI.installDefaults(BasicTreeUI.java:6
99)
       at javax.swing.plaf.basic.BasicTreeUI.installUI(BasicTreeUI.java:630)
       at javax.swing.plaf.metal.MetalTreeUI.installUI(MetalTreeUI.java:95)
       at javax.swing.JComponent.setUI(JComponent.java:673)
       at javax.swing.JTree.setUI(JTree.java:678)
       at javax.swing.JTree.updateUI(JTree.java:694)
       at javax.swing.JTree.<init>(JTree.java:649)
       at javax.swing.JTree.<init>(JTree.java:547)
       at sun.kernel.SwingTest.main(SwingTest.java:38)