在JB9环境下将ejb生成Web服务出现错误

weblogic.xml.schema.binding.BindingException: Invalid class received: interface cims.Cart loaded from D:/cims/classes/cims/Cart.class.  All classes that will
    be serialized or deserialized must be non-interface, non-abstract classes that provide a public default constructor

请教各位大牛如何解决
--
FROM 166.111.82.*