java.lang.NullPointerException at org.netbeans.mdr.util.IOUtils.readMOFID(IOUtils.java:364) at org.netbeans.mdr.util.IOUtils.read(IOUtils.java:479) at org.netbeans.mdr.util.IOUtils.read(IOUtils.java:273) at org.netbeans.mdr.storagemodel.StorableObject.read(StorableObject.java:385) at org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeDatabase.readStreamable(BtreeDatabase.java:906) at org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeDatabase.getRecord(BtreeDatabase.java:974) at org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeDatabase.getIfExists(BtreeDatabase.java:719) at org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeDatabase.getIfExists(BtreeDatabase.java:699) at org.netbeans.mdr.persistence.btreeimpl.btreestorage.BtreeDatabase.get(BtreeDatabase.java:734) at org.netbeans.mdr.storagemodel.MdrStorage.getObject(MdrStorage.java:621) at org.netbeans.mdr.handlers.BaseObjectHandler._getDelegate(BaseObjectHandler.java:451) at org.netbeans.mdr.handlers.InstanceHandler.getInstanceDelegate(InstanceHandler.java:48) at org.netbeans.mdr.handlers.InstanceHandler._handleGet(InstanceHandler.java:193) at org.netbeans.jmi.java.source.JavaClassSource$Impl.getModifiers(Unknown Source) at org.netbeans.modules.classmodel.jmiimpl.physical.JavaClassImpl.isInterface(Unknown Source) at org.netbeans.jmi.java.source.JavaClassSource$Impl.isInterface(Unknown Source) at org.netbeans.modules.javaui.looks.JavaClassLook.iconBase(Unknown Source) at org.netbeans.spi.looks.DefaultLook.findIcon(DefaultLook.java:427) at org.netbeans.spi.looks.DefaultLook.getIcon(DefaultLook.java:164) at org.netbeans.spi.looks.ProxyLook.getIcon(ProxyLook.java:340) at org.netbeans.api.looks.LookNode.getIcon(LookNode.java:622) at org.openide.explorer.view.NodeRenderer$Tree.getTreeCellRendererComponent(NodeRenderer.java:255) at org.openide.explorer.view.NodeRenderer.getTreeCellRendererComponent(NodeRenderer.java:101) at javax.swing.plaf.basic.BasicTreeUI.paintRow(BasicTreeUI.java:1375) at javax.swing.plaf.basic.BasicTreeUI.paint(BasicTreeUI.java:1171) at javax.swing.plaf.metal.MetalTreeUI.paint(MetalTreeUI.java:143) at javax.swing.plaf.ComponentUI.update(ComponentUI.java:142) at javax.swing.JComponent.paintComponent(JComponent.java:537) at javax.swing.JComponent.paint(JComponent.java:804) at org.openide.explorer.view.TreeView$ExplorerTree.paint(TreeView.java:1432) at javax.swing.JComponent.paintChildren(JComponent.java:643) at javax.swing.JComponent.paintWithOffscreenBuffer(JComponent.java:4742) at javax.swing.JComponent.paintDoubleBuffered(JComponent.java:4688) at javax.swing.JComponent._paintImmediately(JComponent.java:4632) at javax.swing.JComponent.paintImmediately(JComponent.java:4464) at javax.swing.RepaintManager.paintDirtyRegions(RepaintManager.java:404) [catch] at javax.swing.SystemEventQueueUtilities$ComponentWorkRequest.run(SystemEventQueueUtilities.java:117) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:178) at java.awt.EventQueue.dispatchEvent(EventQueue.java:443) at java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:191) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:144) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:138) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:130) at java.awt.EventDispatchThread.run(EventDispatchThread.java:98)