java.lang.ClassCastException: org.netbeans.modules.db.mysql.ServerNode cannot be cast to java.lang.Comparable
        at java.util.TreeMap.put(TreeMap.java:542)
        at java.util.TreeSet.add(TreeSet.java:238)
        at java.util.AbstractCollection.addAll(AbstractCollection.java:305)
        at java.util.TreeSet.addAll(TreeSet.java:295)
        at org.openide.nodes.Children$Array.add(Children.java:1493)
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo$1.run(RootNodeInfo.java:194)
        at org.openide.util.Mutex.postRequest(Mutex.java:1251)
        at org.openide.util.Mutex.postWriteRequest(Mutex.java:582)
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo.postUpdateChildren(RootNodeInfo.java:188)
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo.updateRegisteredNodes(RootNodeInfo.java:180)
        at org.netbeans.modules.db.explorer.infos.RootNodeInfo.stateChanged(RootNodeInfo.java:243)
        at org.netbeans.modules.dbapi.DbNodeLoaderImpl.stateChanged(DbNodeLoaderImpl.java:98)
        at org.netbeans.modules.db.mysql.ServerNodeProvider.notifyChange(ServerNodeProvider.java:96)
        at org.netbeans.modules.db.mysql.ServerNodeProvider.setRegistered(ServerNodeProvider.java:85)
        at org.netbeans.modules.db.mysql.Installer$RegisterMySQL.registerProvider(Installer.java:188)
        at org.netbeans.modules.db.mysql.Installer$RegisterMySQL.findAndRegisterMySQL(Installer.java:152)
        at org.netbeans.modules.db.mysql.Installer$RegisterMySQL.run(Installer.java:99)
        at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:561)
        at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:986)