Bug exists in FCS RC5 FFJ build.

If Tomcat 4.0 node was expanded too early after
enabling TC plugin,
then NPE is thrown and no TC installations are
available underneath
this node.

How to reproduce:

1. Add external TC installation (it takes more
time for TC plugin to initialize both internal and
external installations).
2. Disable TC plugin
3. Enable TC plugin and try to expand Tomcat 4.0
node immedeatly after it appears in the Runtime
tab. Observe the following NPE and notice that no
TC istallations appears after that:

Thu May 23 20:52:47 PDT 2002:
java.lang.NullPointerException: <no message>
java.lang.NullPointerException
        at
org.netbeans.modules.tomcat.tomcat40.Tomcat40Children.createNodes(Tomcat40Children.java:65)
        at
org.openide.nodes.Children$Keys$KE.nodes(Children.java:1826)
        at
org.openide.nodes.ChildrenArray.nodesFor(ChildrenArray.java:125)
        at
org.openide.nodes.Children$Info.nodes(Children.java:929)
        at
org.openide.nodes.Children.updateAdd(Children.java:737)
        at
org.openide.nodes.Children.setEntries(Children.java:526)
        at
org.openide.nodes.Children$3.run(Children.java:1719)
        at
org.openide.util.Mutex.leave(Mutex.java:604)
        at
org.openide.util.Mutex.readAccess(Mutex.java:173)
        at
org.openide.explorer.view.VisualizerNode.getChildren(VisualizerNode.java:147)
        at
org.openide.explorer.view.VisualizerNode.getChildCount(VisualizerNode.java:187)
        at
javax.swing.tree.DefaultTreeModel.getChildCount(DefaultTreeModel.java:168)
        at
javax.swing.tree.VariableHeightLayoutCache$TreeStateNode.expand(VariableHeightLayoutCache.java:1461)
        at
javax.swing.tree.VariableHeightLayoutCache$TreeStateNode.expand(VariableHeightLayoutCache.java:1270)
        at
javax.swing.tree.VariableHeightLayoutCache.ensurePathIsExpanded(VariableHeightLayoutCache.java:966)
        at
javax.swing.tree.VariableHeightLayoutCache.setExpandedState(VariableHeightLayoutCache.java:164)
        at
javax.swing.plaf.basic.BasicTreeUI.updateExpandedDescendants(BasicTreeUI.java:1494)
        at
javax.swing.plaf.basic.BasicTreeUI$TreeExpansionHandler.treeExpanded(BasicTreeUI.java:2312)
        at
javax.swing.JTree.fireTreeExpanded(JTree.java:2238)
        at
javax.swing.JTree.setExpandedState(JTree.java:3009)
        at
javax.swing.JTree.expandPath(JTree.java:1744)
        at
javax.swing.plaf.basic.BasicTreeUI.toggleExpandState(BasicTreeUI.java:2093)
        at
javax.swing.plaf.basic.BasicTreeUI.handleExpandControlClick(BasicTreeUI.java:2080)
        at
javax.swing.plaf.basic.BasicTreeUI.checkForClickInExpandControl(BasicTreeUI.java:2034)
        at
javax.swing.plaf.basic.BasicTreeUI$MouseHandler.handleSelection(BasicTreeUI.java:2809)
        at
javax.swing.plaf.basic.BasicTreeUI$MouseHandler.mousePressed(BasicTreeUI.java:2779)
        at
java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:218)
        at
java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:217)
        at
java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:217)
        at
java.awt.AWTEventMulticaster.mousePressed(AWTEventMulticaster.java:217)
        at
java.awt.Component.processMouseEvent(Component.java:5018)
        at
java.awt.Component.processEvent(Component.java:4818)
        at
java.awt.Container.processEvent(Container.java:1380)
        at
java.awt.Component.dispatchEventImpl(Component.java:3526)
        at
java.awt.Container.dispatchEventImpl(Container.java:1437)
        at
java.awt.Component.dispatchEvent(Component.java:3367)
        at
java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:3214)
        at
java.awt.LightweightDispatcher.processMouseEvent(Container.java:2926)
        at
java.awt.LightweightDispatcher.dispatchEvent(Container.java:2859)
        at
java.awt.Container.dispatchEventImpl(Container.java:1423)
        at
java.awt.Window.dispatchEventImpl(Window.java:1566)
        at
java.awt.Component.dispatchEvent(Component.java:3367)
[catch] at
java.awt.EventQueue.dispatchEvent(EventQueue.java:445)
        at
java.awt.EventDispatchThread.pumpOneEventForHierarchy(EventDispatchThread.java:190)
        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)