java.lang.NullPointerException
         at
org.netbeans.modules.java.JavaNode$StateUpdater.propertyChange(JavaNode.java:875)
         at
java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:152)
         at
org.openide.util.SharedClassObject.firePropertyChange(SharedClassObject.java:334)
         at
org.openide.options.SystemOption.firePropertyChange(SystemOption.java:82)
         at
org.openide.options.SystemOption.readExternal(SystemOption.java:262)
         at
org.openide.options.ContextSystemOption.readExternal(ContextSystemOption.java:111)
         at
org.netbeans.modules.java.settings.JavaSettings.readExternal(JavaSettings.java:463)
         at
org.openide.util.SharedClassObject$WriteReplace.readObject(SharedClassObject.java:475)
         at java.lang.reflect.Method.invoke(Native Method)
         at
java.io.ObjectInputStream.invokeObjectReader(ObjectInputStream.java:2214)
         at
java.io.ObjectInputStream.inputObject(ObjectInputStream.java:1411)
         at java.io.ObjectInputStream.readObject(ObjectInputStream.java:386)
         at java.io.ObjectInputStream.readObject(ObjectInputStream.java:236)
         at Deserialize.atest.read(atest.java:33)
         at Deserialize.atest.main(atest.java:72)
         at java.lang.reflect.Method.invoke(Native Method)
         at
org.openide.execution.ThreadExecutor.executeClass(ThreadExecutor.java:132)
         at
org.openide.execution.ThreadExecutor$TERunnable.run(ThreadExecutor.java:209)
         at
org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:118)?m@