单项选择题 A developer is designing the presentation tier for a web application that relies on a complex session bean.The session bean is still being developed and the APIs for it are NOT finalized. Any changes to the sessionbean API directly impacts the development of the presentation tier.  Which design pattern provides a meansto manage the uncertainty in the API？（）

多项选择题 WhichtwoarecharacteristicsoftheFrontControllerpattern？（）

单项选择题 A developer is designing a web application that must support multiple interfaces， including： an XML web service for B2B HTML for web-based clients WML for wireless customers. Which designpattern provides a solution for this problem？（）