FULL PRODUCT VERSION :
java version "1.6.0_11"
Java(TM) SE Runtime Environment (build 1.6.0_11-b03)
Java HotSpot(TM) Client VM (build 11.0-b16, mixed mode, sharing)


ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows XP [Version 5.1.2600]

EXTRA RELEVANT SYSTEM CONFIGURATION :
Problem occurs in Java 1.6.0 Update 07, 11 and 21

A DESCRIPTION OF THE PROBLEM :
We have a custom version of JXTreeTable by swingx.
If the tree is expanded and we sort on of the table colums (which also sorts the tree leafs) the NPE arises:

Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.plaf.basic.BasicTreeUI$Handler.treeNodesChanged(Unknown Source)
at javax.swing.tree.DefaultTreeModel.fireTreeNodesChanged(Unknown Source)
at xxx.gui.treetable.XXXTreeTableColumnModel.sortLeafes(XXXTreeTableColumnModel.java:169)


The problem seems to be that getPathBounds(JTree tree, TreePath path) returns null, but is not checked.

Is see two possibilities:
1. getPathBounds() may not return null or
2. the callers have to check if the return value is null (seems there are more of this constructs that make problems e.g. in 6671481)

I can't give you a testcase, because our source is to complex.

But I can give you an extract of out sortleafs-methode:
    public void sortLeafes(Attribut<T,?> column, boolean ascending){
        List<AttributNode<?>> lastLevelNodes = getLastLevelNodes();
        for (AttributNode<?> node : lastLevelNodes) {
            Enumeration<?> ch = node.children();
            List<LeafNode<?>> orig = new ArrayList<LeafNode<?>>();
            while (ch.hasMoreElements()) {
                orig.add((LeafNode<?>) ch.nextElement());
            }
            int size = orig.size();
            if (size > 0) {
                int[] idx = new int[size];
                int i = 0;
                LeafNode<?>[] from = orig.toArray(new LeafNode<?>[size]);
                LeafNode<?>[] sorted = from.clone();
                shuttlesort(from, sorted, 0, size, column, ascending);
                node.removeAllChildren();
                for (LeafNode<?> leaf : sorted) {
                    node.add(leaf);
                    idx[i]=i++;
                }
                fireTreeNodesChanged(this, node.getPath(), idx, sorted);
            }
        }
    }



ERROR MESSAGES/STACK TRACES THAT OCCUR :
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at javax.swing.plaf.basic.BasicTreeUI$Handler.treeNodesChanged(Unknown Source)
at javax.swing.tree.DefaultTreeModel.fireTreeNodesChanged(Unknown Source)
at xxx.gui.treetable.XXXTreeTableColumnModel.sortLeafes(XXXTreeTableColumnModel.java:169)
at xxx.gui.ObjektTabelle.sortTreeLeafes(ObjektTabelle.java:597)
at xxx.gui.TablePanel.sortTreeLeafes(TablePanel.java:1226)
at xxx.gui.TableContainer.mouseClicked(TableContainer.java:176)
at java.awt.AWTEventMulticaster.mouseClicked(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at javax.swing.JComponent.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForFilters(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForFilter(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)


REPRODUCIBILITY :
This bug can be reproduced always.