java.lang.IllegalStateException: Too many org.netbeans.modules.maven.nodes.SourcesNodeFactory$NList$1 (2) in shared RequestProcessor; create your own
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:416)
   at org.netbeans.modules.maven.nodes.SourcesNodeFactory$NList.stateChanged(SourcesNodeFactory.java:141)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:130)
   at org.openide.util.ChangeSupport.fireChange(ChangeSupport.java:116)
   at org.netbeans.spi.project.support.LookupProviderSupport$SourcesImpl.setLookup(LookupProviderSupport.java:278)
   at org.netbeans.spi.project.support.LookupProviderSupport$SourcesImpl.access$200(LookupProviderSupport.java:253)
   at org.netbeans.spi.project.support.LookupProviderSupport$SourcesMerger.merge(LookupProviderSupport.java:248)
   at org.netbeans.spi.project.support.LookupProviderSupport$SourcesMerger.merge(LookupProviderSupport.java:237)
   at org.netbeans.spi.project.support.LookupProviderSupport$DelegatingLookupImpl.doDelegate(LookupProviderSupport.java:223)
   at org.netbeans.spi.project.support.LookupProviderSupport$DelegatingLookupImpl.resultChanged(LookupProviderSupport.java:157)
   at org.openide.util.lookup.AbstractLookup$NotifyListeners.run(AbstractLookup.java:521)
   at org.openide.util.lookup.AbstractLookup.notifyIn(AbstractLookup.java:301)
   at org.openide.util.lookup.AbstractLookup.addPairImpl(AbstractLookup.java:243)
   at org.openide.util.lookup.AbstractLookup.addPair(AbstractLookup.java:210)
   at org.openide.util.lookup.AbstractLookup$Content.addPair(AbstractLookup.java:1219)
   at org.openide.util.lookup.InstanceContent.add(InstanceContent.java:87)
   at org.netbeans.modules.maven.runjar.J2seLookupProvider$Provider.doCheckJ2se(J2seLookupProvider.java:99)
   at org.netbeans.modules.maven.runjar.J2seLookupProvider$Provider.checkJ2se(J2seLookupProvider.java:92)
   at org.netbeans.modules.maven.runjar.J2seLookupProvider$Provider.propertyChange(J2seLookupProvider.java:85)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:339)
   at java.beans.PropertyChangeSupport.firePropertyChange(PropertyChangeSupport.java:276)
   at org.netbeans.modules.maven.api.NbMavenProject.doFireReload(NbMavenProject.java:460)
   at org.netbeans.modules.maven.api.NbMavenProject.access$200(NbMavenProject.java:82)
   at org.netbeans.modules.maven.api.NbMavenProject$AccessorImpl.doFireReload(NbMavenProject.java:123)
   at org.netbeans.modules.maven.NbMavenProjectImpl.fireProjectReload(NbMavenProjectImpl.java:544)
   at org.netbeans.modules.maven.api.NbMavenProject.fireProjectReload(NbMavenProject.java:454)
   at org.netbeans.modules.maven.api.NbMavenProject.fireMavenProjectReload(NbMavenProject.java:473)
   at org.netbeans.modules.maven.execute.MavenCommandLineExecutor$1.run(MavenCommandLineExecutor.java:217)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1417)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:1955)