java.lang.ArrayIndexOutOfBoundsException: 8 >= 7
        at java.util.Vector.removeElementAt(Vector.java:511)
        at javax.swing.tree.VariableHeightLayoutCache$TreeStateNode.collapse(VariableHeightLayoutCache.java:1583)
        at javax.swing.tree.VariableHeightLayoutCache$TreeStateNode.collapse(VariableHeightLayoutCache.java:1277)
        at javax.swing.tree.VariableHeightLayoutCache.setExpandedState(VariableHeightLayoutCache.java:170)
        at javax.swing.plaf.basic.BasicTreeUI$Handler.treeCollapsed(BasicTreeUI.java:3731)
        at javax.swing.JTree.fireTreeCollapsed(JTree.java:2690)
        at javax.swing.JTree.setExpandedState(JTree.java:3406)
        at javax.swing.JTree.collapsePath(JTree.java:2191)
        at javax.swing.plaf.basic.BasicTreeUI.toggleExpandState(BasicTreeUI.java:2220)
        at javax.swing.plaf.basic.BasicTreeUI.handleExpandControlClick(BasicTreeUI.java:2196)
        at javax.swing.plaf.basic.BasicTreeUI.checkForClickInExpandControl(BasicTreeUI.java:2154)
        at javax.swing.plaf.basic.BasicTreeUI$Handler.handleSelection(BasicTreeUI.java:3516)
        at javax.swing.plaf.basic.BasicTreeUI$Handler.mousePressed(BasicTreeUI.java:3464)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:262)
        at java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:262)
        at java.awt.Component.processMouseEvent(Component.java:6131)
        at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
        at java.awt.Component.processEvent(Component.java:5899)
        at java.awt.Container.processEvent(Container.java:2023)
        at java.awt.Component.dispatchEventImpl(Component.java:4501)
        at java.awt.Container.dispatchEventImpl(Container.java:2081)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.LightweightDispatcher.retargetMouseEvent(LightweightDispatcher.java:4301)
        at java.awt.LightweightDispatcher.processMouseEvent(LightweightDispatcher.java:3962)
        at java.awt.LightweightDispatcher.dispatchEvent(LightweightDispatcher.java:3895)
        at java.awt.Container.dispatchEventImpl(Container.java:2067)
        at java.awt.Window.dispatchEventImpl(Window.java:2458)
        at java.awt.Component.dispatchEvent(Component.java:4331)
        at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
        at org.netbeans.core.TimableEventQueue.dispatchEvent(TimableEventQueue.java:104)
        at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269)
        at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184)
        at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169)
        at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161)
        at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)