Strategy pattern in spring --MessageSource

/**
 * Strategy interface for resolving messages, with support for the parameterization
 * and internationalization of such messages.
 *
 * <p>Spring provides two out-of-the-box implementations for production:
 * <ul>
* <li>{@link org.springframework.context.support.ResourceBundleMessageSource},
 * built on top of the standard {@link java.util.ResourceBundle}
 * <li>{@link org.springframework.context.support.ReloadableResourceBundleMessageSource},
 * being able to reload message definitions without restarting the VM
  * </ul>
*
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @see org.springframework.context.support.ResourceBundleMessageSource
 * @see org.springframework.context.support.ReloadableResourceBundleMessageSource
 */
public interface MessageSource