org.apache.dubbo.config.spring.ServiceBean#getSpringContext looks like a hack, we need to remove it.
private static final Logger logger = LoggerFactory.getLogger(SpringExtensionFactory.class);
    private static final Set<ApplicationContext> contexts = new ConcurrentHashSet<ApplicationContext>();
    public static void addApplicationContext(ApplicationContext context) {
        contexts.add(context);
    }
    public static void removeApplicationContext(ApplicationContext context) {
        contexts.remove(context);
    }
    
    public static void clearContexts() {
        contexts.clear();
    }
    @Override
    @SuppressWarnings("unchecked")