Bug 93287 LTK Core Refactoring triggered on shutdown of JavaPlugin
org.eclipse.ltk.core.refactoring/src/org/eclipse/ltk/core/refactoring/RefactoringCore.java
* stack.
	 * 
	 * @return the refactoring undo manager.
	 */
	public static IUndoManager getUndoManager() {
		if (fgUndoManager == null)
			fgUndoManager= createUndoManager();
		return fgUndoManager;
	}
	
	/**
	 * When condition checking is performed for a refactoring then the
	 * condition check is interpreted as failed if the refactoring status
	 * severity return from the condition checking operation is equal
	 * or greater than the value returned by this method. 
	 * 
	 * @return the condition checking failed severity
	 */
	public static int getConditionCheckingFailedSeverity() {
		return RefactoringCorePreferences.getStopSeverity();
	}
	
	/**
	 * Returns the query factory.
	 * 
	 * @return the query factory
	 * 
	 * @since 3.1
	 */
	public static IValidationCheckResultQueryFactory getQueryFactory() {