Bug 92988 [Viewers] potential NPE in AbstractTreeViewer
I0426, found with FindBugs 1. AbstractTreeViewer line 832 invokes "siblings.length", but the "if" statement above implies that siblings could be null here. 2. StringFieldEditor line 187 does an unnecessary null check since Text.getText() never returns null (FindBugs was using this to point to line 190 as a potential NPE).
bundles/org.eclipse.jface/src/org/eclipse/jface/viewers/AbstractTreeViewer.java
* 
     * @param level
     *           non-negative level, or <code>ALL_LEVELS</code> to expand all
     *           levels of the tree
     */
    public void expandToLevel(int level) {
        expandToLevel(getRoot(), level);
    }
    /**
     * Expands all ancestors of the given element so that the given element
     * becomes visible in this viewer's tree control, and then expands the
     * subtree rooted at the given element to the given level.
     * 
     * @param element
     *           the element
     * @param level
     *           non-negative level, or <code>ALL_LEVELS</code> to expand all
     *           levels of the tree
     */
    public void expandToLevel(Object element, int level) {
        Widget w = internalExpand(element, true);
        if (w != null)
            internalExpandToLevel(w, level);
    }
    /**
     * Fires a tree collapsed event. Only listeners registered at the time this
     * method is called are notified.
     * 
     * @param event
     *           the tree expansion event