When I start a NetBeans 7.1 development build using JDK 7b143 using Nimbus L&F, the following exception is thrown:

java.lang.NullPointerException
at javax.swing.plaf.nimbus.NimbusLookAndFeel.addDefault(NimbusLookAndFeel.java:593)
at javax.swing.plaf.nimbus.NimbusLookAndFeel.access$700(NimbusLookAndFeel.java:64)
at javax.swing.plaf.nimbus.NimbusLookAndFeel$DefaultsListener.propertyChange(NimbusLookAndFeel.java:608)
at java.beans.PropertyChangeSupport.fire(PropertyChangeSupport.java:335)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:327)
at javax.swing.event.SwingPropertyChangeSupport.firePropertyChange(SwingPropertyChangeSupport.java:92)
at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:263)
at javax.swing.UIDefaults.firePropertyChange(UIDefaults.java:844)
at javax.swing.UIDefaults.put(UIDefaults.java:348)
at org.netbeans.swing.dirchooser.Module.install(Module.java:93)
at org.netbeans.swing.dirchooser.Module.restored(Module.java:73)
at org.netbeans.core.startup.NbInstaller.loadCode(NbInstaller.java:426)
[catch] at org.netbeans.core.startup.NbInstaller.load(NbInstaller.java:366)