java.util.ConcurrentModificationException
   at java.util.TreeMap$PrivateEntryIterator.nextEntry(TreeMap.java:1115)
   at java.util.TreeMap$KeyIterator.next(TreeMap.java:1169)
   at java.util.AbstractCollection.toArray(AbstractCollection.java:141)
   at java.util.Collections$UnmodifiableCollection.toArray(Collections.java:1058)
   at java.util.ArrayList.addAll(ArrayList.java:530)
   at org.netbeans.modules.db.explorer.node.NodeRegistry.getNodes(NodeRegistry.java:167)
   at org.netbeans.api.db.explorer.node.ChildNodeFactory.createKeys(ChildNodeFactory.java:107)
   at org.openide.nodes.AsynchChildren.run(AsynchChildren.java:206)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.util.ConcurrentModificationException
   at org.openide.util.RequestProcessor$Task.schedule(RequestProcessor.java:1493)
   at org.openide.nodes.AsynchChildren.refresh(AsynchChildren.java:133)
   at org.openide.nodes.ChildFactory.refresh(ChildFactory.java:167)
   at org.netbeans.api.db.explorer.node.ChildNodeFactory.refresh(ChildNodeFactory.java:77)
   at org.netbeans.api.db.explorer.node.BaseNode.update(BaseNode.java:258)
   at org.netbeans.api.db.explorer.node.BaseNode$1.stateChanged(BaseNode.java:205)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:133)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:119)
   at org.netbeans.modules.db.explorer.node.NodeRegistry.stateChanged(NodeRegistry.java:182)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:133)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:119)
   at org.netbeans.api.db.explorer.node.NodeProvider.setNodes(NodeProvider.java:191)
   at org.netbeans.modules.db.explorer.node.ConnectionNodeProvider.initialize(ConnectionNodeProvider.java:114)
   at org.netbeans.modules.db.explorer.node.ConnectionNodeProvider$1.connectionsChanged(ConnectionNodeProvider.java:92)
   at org.netbeans.modules.db.explorer.ConnectionList.fireListeners(ConnectionList.java:166)
   at org.netbeans.modules.db.explorer.ConnectionList.access$000(ConnectionList.java:71)
   at org.netbeans.modules.db.explorer.ConnectionList$1.resultChanged(ConnectionList.java:102)
   at org.openide.util.lookup.AbstractLookup$NotifyListeners.run(AbstractLookup.java:536)
   at org.openide.loaders.FolderLookup$Dispatch.run(FolderLookup.java:314)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1452)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2032)