java.lang.IllegalArgumentException: Comparison method violates its general contract!
   at java.util.ComparableTimSort.mergeHi(ComparableTimSort.java:835)
   at java.util.ComparableTimSort.mergeAt(ComparableTimSort.java:453)
   at java.util.ComparableTimSort.mergeCollapse(ComparableTimSort.java:376)
   at java.util.ComparableTimSort.sort(ComparableTimSort.java:182)
   at java.util.ComparableTimSort.sort(ComparableTimSort.java:146)
   at java.util.Arrays.sort(Arrays.java:472)
   at java.util.Collections.sort(Collections.java:155)
   at org.netbeans.modules.maven.indexer.NexusRepositoryIndexerImpl.find(NexusRepositoryIndexerImpl.java:1346)
   at org.netbeans.modules.maven.indexer.NexusRepositoryIndexerImpl.find(NexusRepositoryIndexerImpl.java:1271)
   at org.netbeans.modules.maven.indexer.api.RepositoryQueries.findResult(RepositoryQueries.java:525)
   at org.netbeans.modules.maven.nodes.AddDependencyPanel$QueryPanel$2.run(AddDependencyPanel.java:1136)
   at org.openide.util.RequestProcessor$Task.run(RequestProcessor.java:1454)
   at org.openide.util.RequestProcessor$Processor.run(RequestProcessor.java:2048)
Caused: org.openide.util.RequestProcessor$SlowItem: task failed due to: java.lang.IllegalArgumentException: Comparison method violates its general contract!
   at org.openide.util.RequestProcessor.post(RequestProcessor.java:424)
   at org.netbeans.modules.maven.nodes.AddDependencyPanel$QueryPanel.find(AddDependencyPanel.java:1123)
   at org.netbeans.modules.maven.nodes.AddDependencyPanel$QueryPanel.stateChanged(AddDependencyPanel.java:1057)
   at org.netbeans.modules.maven.api.customizer.support.DelayedDocumentChangeListener$1.actionPerformed(DelayedDocumentChangeListener.java:76)
   at javax.swing.Timer.fireActionPerformed(Timer.java:312)
   at javax.swing.Timer$DoPostEvent.run(Timer.java:244)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:251)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:727)
   at java.awt.EventQueue.access$200(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:688)
   at java.awt.EventQueue$3.run(EventQueue.java:686)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:697)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:154)
   at java.awt.WaitDispatchSupport$2.run(WaitDispatchSupport.java:182)
   at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:221)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.awt.WaitDispatchSupport.enter(WaitDispatchSupport.java:219)
   at java.awt.Dialog.show(Dialog.java:1082)
   at org.netbeans.core.windows.services.NbPresenter.superShow(NbPresenter.java:1076)
   at org.netbeans.core.windows.services.NbPresenter.doShow(NbPresenter.java:1126)
   at org.netbeans.core.windows.services.NbPresenter.run(NbPresenter.java:1098)
   at org.netbeans.core.windows.services.NbPresenter.run(NbPresenter.java:128)
   at org.openide.util.Mutex.doEventAccess(Mutex.java:1363)
   at org.openide.util.Mutex.readAccess(Mutex.java:273)
   at org.netbeans.core.windows.services.NbPresenter.show(NbPresenter.java:1083)
   at java.awt.Component.show(Component.java:1651)
   at java.awt.Component.setVisible(Component.java:1603)
   at java.awt.Window.setVisible(Window.java:1014)
   at java.awt.Dialog.setVisible(Dialog.java:1005)
   at org.netbeans.core.windows.services.DialogDisplayerImpl$1AWTQuery.showDialog(DialogDisplayerImpl.java:260)
   at org.netbeans.core.windows.services.DialogDisplayerImpl.notify(DialogDisplayerImpl.java:276)
   at org.netbeans.core.windows.services.DialogDisplayerImpl.notify(DialogDisplayerImpl.java:167)
   at org.netbeans.modules.maven.nodes.AddDependencyPanel.show(AddDependencyPanel.java:149)
   at org.netbeans.modules.maven.spi.grammar.DialogFactory.showDependencyDialog(DialogFactory.java:83)
   at org.netbeans.modules.maven.codegen.DependencyGenerator.doInvoke(DependencyGenerator.java:108)
   at org.netbeans.modules.maven.codegen.AbstractGenerator.invoke(AbstractGenerator.java:84)
   at org.netbeans.modules.editor.codegen.GenerateCodePanel.invokeSelected(GenerateCodePanel.java:197)
   at org.netbeans.modules.editor.codegen.GenerateCodePanel.listKeyReleased(GenerateCodePanel.java:143)
   at org.netbeans.modules.editor.codegen.GenerateCodePanel.access$300(GenerateCodePanel.java:66)
   at org.netbeans.modules.editor.codegen.GenerateCodePanel$4.keyReleased(GenerateCodePanel.java:123)
   at java.awt.AWTEventMulticaster.keyReleased(AWTEventMulticaster.java:260)
   at java.awt.Component.processKeyEvent(Component.java:6466)
   at javax.swing.JComponent.processKeyEvent(JComponent.java:2829)
   at java.awt.Component.processEvent(Component.java:6282)
   at java.awt.Container.processEvent(Container.java:2229)
   at java.awt.Component.dispatchEventImpl(Component.java:4861)
   at java.awt.Container.dispatchEventImpl(Container.java:2287)
   at java.awt.Component.dispatchEvent(Component.java:4687)
   at java.awt.KeyboardFocusManager.redispatchEvent(KeyboardFocusManager.java:1895)
   at java.awt.DefaultKeyboardFocusManager.dispatchKeyEvent(DefaultKeyboardFocusManager.java:762)
   at java.awt.DefaultKeyboardFocusManager.preDispatchKeyEvent(DefaultKeyboardFocusManager.java:1027)
   at java.awt.DefaultKeyboardFocusManager.typeAheadAssertions(DefaultKeyboardFocusManager.java:899)
   at java.awt.DefaultKeyboardFocusManager.dispatchEvent(DefaultKeyboardFocusManager.java:727)
   at java.awt.Component.dispatchEventImpl(Component.java:4731)
   at java.awt.Container.dispatchEventImpl(Container.java:2287)
   at java.awt.Window.dispatchEventImpl(Window.java:2719)
   at java.awt.Component.dispatchEvent(Component.java:4687)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:729)
   at java.awt.EventQueue.access$200(EventQueue.java:103)
   at java.awt.EventQueue$3.run(EventQueue.java:688)
   at java.awt.EventQueue$3.run(EventQueue.java:686)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:87)
   at java.awt.EventQueue$4.run(EventQueue.java:702)
   at java.awt.EventQueue$4.run(EventQueue.java:700)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$1.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:699)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:242)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:161)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:150)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:146)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:91)