java.lang.IllegalStateException: Error in org.openide.nodes.EntrySupport$Default with entry Children.Keys.KE[extendedSQLGrammar: false
proceduresAreCallable: false
readOnly: false
maxCharLi,0] from among null in {Children.Keys.KE[extendedSQLGrammar: false
proceduresAreCallable: false
readOnly: false
maxCharLi,0]=Children.Info[Children.Keys.KE[extendedSQLGrammar: false
proceduresAreCallable: false
readOnly: false
maxCharLi,0],length=1], Children.Keys.KE[extendedSQLGrammar: false
proceduresAreCallable: false
readOnly: false
maxCharLi,0]=Children.Info[Children.Keys.KE[extendedSQLGrammar: false
proceduresAreCallable: false
readOnly: false
maxCharLi,0],length=1], Children.Array.AE[]=Children.Info[Children.Array.AE[],length=0], Children.Keys.KE[extendedSQLGrammar: false
proceduresAreCallable: false
readOnly: false
maxCharLi,0]=Children.Info[Children.Keys.KE[extendedSQLGrammar: false
proceduresAreCallable: false
readOnly: false
maxCharLi,0],length=1]} probably caused by faulty key implementation. The key hashCode() 
        at org.openide.nodes.EntrySupport$Default.checkInfo(EntrySupport.java:332)
        at org.openide.nodes.EntrySupport$Default.updateRemove(EntrySupport.java:352)
        at org.openide.nodes.EntrySupport$Default.setEntries(EntrySupport.java:315)
        at org.openide.nodes.Children$Keys$2.run(Children.java:1383)
        at org.openide.util.Mutex.postRequest(Mutex.java:1251)
        at org.openide.util.Mutex.postWriteRequest(Mutex.java:582)
        at org.openide.nodes.Children$Keys.applyKeys(Children.java:1392)
        at org.openide.nodes.Children$Keys.setKeys(Children.java:1337)
        at org.openide.nodes.AsynchChildren.run(AsynchChildren.java:147)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:561)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:986)