docs: public boolean hasService(Class serviceClass)
  	{
  		if (serviceClass == null)
  		{
  			throw new NullPointerException();
  		}
  
  		boolean has;
  		synchronized (services)
  		{
  			has = services.containsKey(serviceClass);
  		}
  		if (!has && getBeanContext() instanceof BeanContextServices)
  		{
  			has = ((BeanContextServices) getBeanContext()).hasService(serviceClass);
  		}
  		return has;
  	}