java.lang.IllegalArgumentException: Libraries array contains a null reference: [null, null]
   at org.netbeans.modules.java.api.common.classpath.ClassPathModifierSupport.handleLibraries(ClassPathModifierSupport.java:449)
   at org.netbeans.modules.java.api.common.classpath.ClassPathModifier.handleLibraries(ClassPathModifier.java:187)
   at org.netbeans.modules.java.api.common.classpath.ClassPathModifier.addLibraries(ClassPathModifier.java:183)
   at org.netbeans.modules.web.project.classpath.DelagatingProjectClassPathModifierImpl.addLibraries(DelagatingProjectClassPathModifierImpl.java:92)
   at org.netbeans.spi.java.project.classpath.ProjectClassPathModifierImplementation$Accessor.addLibraries(ProjectClassPathModifierImplementation.java:426)
   at org.netbeans.api.java.project.classpath.ProjectClassPathModifier.addLibraries(ProjectClassPathModifier.java:97)
   at org.netbeans.modules.junit.ant.ui.JUnitProjectOpenedHook$UpdateToJUnit4Action.actionPerformed(JUnitProjectOpenedHook.java:302)
   at org.netbeans.modules.junit.ant.ui.JUnitProjectOpenedHook$JUnitProblemResolver.resolve(JUnitProjectOpenedHook.java:238)
   at org.netbeans.spi.project.ui.ProjectProblemsProvider$ProjectProblem.resolve(ProjectProblemsProvider.java:284)
   at org.netbeans.modules.project.ui.problems.BrokenReferencesCustomizer.fixActionImpl(BrokenReferencesCustomizer.java:209)
   at org.netbeans.modules.project.ui.problems.BrokenReferencesCustomizer.fixActionPerformed(BrokenReferencesCustomizer.java:197)
   at org.netbeans.modules.project.ui.problems.BrokenReferencesCustomizer.access$500(BrokenReferencesCustomizer.java:73)
   at org.netbeans.modules.project.ui.problems.BrokenReferencesCustomizer$3.actionPerformed(BrokenReferencesCustomizer.java:150)
   at javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:2022)
   at javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2348)
   at javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:402)
   at javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:259)
   at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:252)
   at java.awt.Component.processMouseEvent(Component.java:6535)
   at javax.swing.JComponent.processMouseEvent(JComponent.java:3324)
   at java.awt.Component.processEvent(Component.java:6300)
   at java.awt.Container.processEvent(Container.java:2236)
   at java.awt.Component.dispatchEventImpl(Component.java:4891)
   at java.awt.Container.dispatchEventImpl(Container.java:2294)
   at java.awt.Component.dispatchEvent(Component.java:4713)
   at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4888)
   at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:4525)
   at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:4466)
   at java.awt.Container.dispatchEventImpl(Container.java:2280)
   at java.awt.Window.dispatchEventImpl(Window.java:2750)
   at java.awt.Component.dispatchEvent(Component.java:4713)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:758)
   at java.awt.EventQueue.access$500(EventQueue.java:97)
   at java.awt.EventQueue$3.run(EventQueue.java:709)
   at java.awt.EventQueue$3.run(EventQueue.java:703)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:86)
   at java.awt.EventQueue$4.run(EventQueue.java:731)
   at java.awt.EventQueue$4.run(EventQueue.java:729)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:728)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:109)
   at java.awt.WaitDispatchSupport$2.run(WaitDispatchSupport.java:184)
   at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:229)
   at java.awt.WaitDispatchSupport$4.run(WaitDispatchSupport.java:227)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.awt.WaitDispatchSupport.enter(WaitDispatchSupport.java:227)
   at java.awt.Dialog.show(Dialog.java:1084)
   at org.netbeans.core.windows.services.NbPresenter.superShow(NbPresenter.java:1065)
   at org.netbeans.core.windows.services.NbPresenter.doShow(NbPresenter.java:1115)
   at org.netbeans.core.windows.services.NbPresenter.run(NbPresenter.java:1087)
   at org.netbeans.core.windows.services.NbPresenter.run(NbPresenter.java:128)
   at org.netbeans.modules.openide.util.NbMutexEventProvider$Event.doEventAccess(NbMutexEventProvider.java:138)
   at org.netbeans.modules.openide.util.NbMutexEventProvider$Event.readAccess(NbMutexEventProvider.java:98)
   at org.netbeans.modules.openide.util.LazyMutexImplementation.readAccess(LazyMutexImplementation.java:94)
   at org.openide.util.Mutex.readAccess(Mutex.java:218)
   at org.netbeans.core.windows.services.NbPresenter.show(NbPresenter.java:1072)
   at java.awt.Component.show(Component.java:1673)
   at java.awt.Component.setVisible(Component.java:1625)
   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:266)
   at org.netbeans.core.windows.services.DialogDisplayerImpl.notify(DialogDisplayerImpl.java:282)
   at org.netbeans.core.windows.services.DialogDisplayerImpl.notify(DialogDisplayerImpl.java:173)
   at org.netbeans.modules.project.ui.problems.BrokenReferencesImpl$1.run(BrokenReferencesImpl.java:140)
   at org.netbeans.core.windows.WindowManagerImpl$Exclusive$1.run(WindowManagerImpl.java:1563)
   at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:311)
   at java.awt.EventQueue.dispatchEventImpl(EventQueue.java:756)
   at java.awt.EventQueue.access$500(EventQueue.java:97)
   at java.awt.EventQueue$3.run(EventQueue.java:709)
   at java.awt.EventQueue$3.run(EventQueue.java:703)
   at java.security.AccessController.doPrivileged(AccessController.java:0)
   at java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:76)
   at java.awt.EventQueue.dispatchEvent(EventQueue.java:726)
   at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:159)
   at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:201)
   at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:116)
   at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:105)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
   at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:93)
   at java.awt.EventDispatchThread.run(EventDispatchThread.java:82)