This bug was originally marked as duplicate of bug 138391, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.

Build: NetBeans IDE 6.9 Beta (Build 201004200117)
VM: Java HotSpot(TM) 64-Bit Server VM, 16.3-b01, Java(TM) SE Runtime Environment, 1.6.0_20-b02
OS: Windows 7

User Comments:
lazarius: Scrolling trough Java editor window.

GUEST: Opening file *.java

lazarius: Switched to a different editor tab in the Java editor window.




Stacktrace: 
java.lang.AssertionError: Attr.visitNewClass tree [new PrivilegedAction(){
    
    () {
        super();
    }
    
    public Object run() {
        pumpEventsForFilter.run();
        return null;
    }
}] with constructor type [null] has symbol [access error wrongSym=Object()] of kind [ 66]
   at com.sun.tools.javac.comp.Attr.visitNewClass(Attr.java:1659)
   at com.sun.tools.javac.tree.JCTree$JCNewClass.accept(JCTree.java:1355)
   at com.sun.tools.javac.comp.Attr.attribTree(Attr.java:431)
   at com.sun.tools.javac.comp.Attr.attribArgs(Attr.java:500)
   at com.sun.tools.javac.comp.Attr.visitApply(Attr.java:1392)
   at com.sun.tools.javac.tree.JCTree$JCMethodInvocation.accept(JCTree.java:1304)