java.lang.AssertionError
   at org.netbeans.modules.maven.indexer.NexusRepositoryIndexerImpl.loadIndexingContext(NexusRepositoryIndexerImpl.java:256)
   at org.netbeans.modules.maven.indexer.NexusRepositoryIndexerImpl.access$400(NexusRepositoryIndexerImpl.java:152)
   at org.netbeans.modules.maven.indexer.NexusRepositoryIndexerImpl$3.run(NexusRepositoryIndexerImpl.java:525)
   at org.netbeans.modules.maven.indexer.NexusRepositoryIndexerImpl$3.run(NexusRepositoryIndexerImpl.java:523)
   at org.openide.util.Mutex.writeAccess(Mutex.java:436)
   at org.netbeans.modules.maven.indexer.NexusRepositoryIndexerImpl.updateIndexWithArtifacts(NexusRepositoryIndexerImpl.java:523)
   at org.netbeans.modules.maven.indexer.api.RepositoryIndexer.updateIndexWithArtifacts(RepositoryIndexer.java:74)
   at org.netbeans.modules.maven.ActionProviderImpl$2.taskFinished(ActionProviderImpl.java:295)
   at org.openide.util.Task.notifyFinished(Task.java:231)
   at org.netbeans.core.execution.ExecutorTaskImpl.finished(ExecutorTaskImpl.java:89)
   at org.netbeans.core.execution.RunClassThread.run(RunClassThread.java:176)