Bug 163357 [Viewers] NullPointerException on AbstractTreeViewer.remove(path, index)
I20061102-1715 It's possible to get an NPE when removing an element from a tree viewer. The remove API accepts a "parent path" and "child index". It is possible to specify an empty tree path for the parent to indicate the root element. However, the remove code eventually trys to find the widget associated with the "last segment" of the parent path. This results in null, and an NPE: Caused by: java.lang.NullPointerException at org.eclipse.jface.viewers.CustomHashtable.hashCode(CustomHashtable.java:265) at org.eclipse.jface.viewers.CustomHashtable.get(CustomHashtable.java:237) at org.eclipse.jface.viewers.StructuredViewer.findItems(StructuredViewer.java:769) at org.eclipse.jface.viewers.AbstractTreeViewer.internalFindItem(AbstractTreeViewer.java:173) at org.eclipse.jface.viewers.AbstractTreeViewer.internalFindItems(AbstractTreeViewer.java:153) at org.eclipse.jface.viewers.TreeViewer$8.run(TreeViewer.java:1017) at org.eclipse.jface.viewers.StructuredViewer.preservingSelection(StructuredViewer.java:1326) at org.eclipse.jface.viewers.TreeViewer.remove(TreeViewer.java:1005) at org.eclipse.debug.internal.ui.viewers.model.ChildrenUpdate.performUpdate(ChildrenUpdate.java:62) at org.eclipse.debug.internal.ui.viewers.model.ViewerUpdateMonitor$1.runInUIThread(ViewerUpdateMonitor.java:43) at org.eclipse.ui.progress.UIJob$1.run(UIJob.java:94) at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35) at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:123) ... 20 more
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/TreeViewer.java
* @param element
	 *            the element
	 * @param column
	 *            the column number
	 * @since 3.1
	 */
	public void editElement(Object element, int column) {
		treeViewerImpl.editElement(element, column);
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.ColumnViewer#getCellEditors()
	 */
	public CellEditor[] getCellEditors() {
		return treeViewerImpl.getCellEditors();
	}
	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.ColumnViewer#getCellModifier()
	 */
	public ICellModifier getCellModifier() {
		return treeViewerImpl.getCellModifier();
	}
	/*
	 * (non-Javadoc) Method declared in AbstractTreeViewer.
	 */
	protected Item[] getChildren(Widget o) {
		if (o instanceof TreeItem) {