Caused: java.lang.NoSuchMethodException: org.netbeans.modules.web.jsf.JSFConfigMultiviewDescriptor$JSFConfigMultiviewElement.<init>()
at java.lang.Class.getConstructor0(Class.java:2706)
at java.lang.Class.getDeclaredConstructor(Class.java:1985)
at org.openide.windows.TopComponent$Replacer.readObject(TopComponent.java:1469)
Caused: java.io.IOException
at org.openide.windows.TopComponent$Replacer.readObject(TopComponent.java:1525)
at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1849)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
at org.netbeans.core.multiview.MultiViewPeer.peerReadExternal(MultiViewPeer.java:442)
at org.netbeans.core.multiview.MultiViewCloneableTopComponent.readExternal(MultiViewCloneableTopComponent.java:201)
at org.openide.windows.TopComponent$Replacer.readObject(TopComponent.java:1478)
at sun.reflect.GeneratedMethodAccessor11.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974)
at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1849)
at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1753)
at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1329)
at java.io.ObjectInputStream.readObject(ObjectInputStream.java:351)
at org.netbeans.modules.settings.convertors.XMLSettingsSupport$SettingsRecognizer.readSerial(XMLSettingsSupport.java:544)
at org.netbeans.modules.settings.convertors.XMLSettingsSupport$SettingsRecognizer.instanceCreate(XMLSettingsSupport.java:576)
at org.netbeans.modules.settings.convertors.SerialDataConvertor$SettingsInstance.instanceCreate(SerialDataConvertor.java:420)
The problem can be easily fixed by removing the particular file (MultiView-PageFlow#007CXML#007C.setting in my case), or if you are lazy, all [XYZ].setting files from: .netbeans\6.5\config\Windows2Local\Components. It will have similar effect to the "Reset Window" action.
It happens not very often: exactly 2 times in my case (after the installation of JavaFX and IceFaces extension).