OPERATING SYSTEM(S):
Microsoft Windows XP [Version 5.1.2600]

FULL JDK VERSION(S):
java version "1.6.0_11"
Java(TM) SE Runtime Environment (build 1.6.0_11-b03)
Java HotSpot(TM) Client VM (build 11.0-b16, mixed mode)

DESCRIPTION:
Similar NPEs were fixed in 6u10 under CR 6612359.

Start JConsole from the commandline using the Nimbus look & feel:

jconsole -J-Dswing.defaultlaf=com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel

The main window opens, but when creating the 'Connect to..' dialog, we get a NPE:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at sun.tools.jconsole.VMPanel.setUI(VMPanel.java:146)
at javax.swing.JTabbedPane.updateUI(JTabbedPane.java:230)
at javax.swing.JTabbedPane.<init>(JTabbedPane.java:189)
at javax.swing.JTabbedPane.<init>(JTabbedPane.java:154)
at sun.tools.jconsole.VMPanel.<init>(VMPanel.java:82)
at sun.tools.jconsole.JConsole$4.run(JConsole.java:531)
at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:597)
at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)