Bug 15301 'show in packages view' - does not work fo java files not in source folders
20020502 open a java file that is in a resource folder (so it is not an ICompilationUnit - just a file with .java extension) 'show in packages view' is present in the context menu but it does nothing
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/viewsupport/BaseJavaElementContentProvider.java
* Returns whether the members are provided when asking
	 * for a CU's or ClassFile's children.
	 */
	public void setProvideMembers(boolean b) {
		fProvideMembers= b;
	}
	/* (non-Javadoc)
	 * Method declared on IStructuredContentProvider.
	 */
	public Object[] getElements(Object parent) {
		return getChildren(parent);
	}
	
	/* (non-Javadoc)
	 * Method declared on IContentProvider.
	 */
	public void inputChanged(Viewer viewer, Object oldInput, Object newInput) {
	}
	/* (non-Javadoc)
	 * Method declared on IContentProvider.
	 */
	public void dispose() {
	}
	/* (non-Javadoc)
	 * Method declared on ITreeContentProvider.
	 */
	public Object[] getChildren(Object element) {
		if (!exists(element))
			return NO_CHILDREN;