为什么以及如何在Java web应用程序中使用序列化?

I've been working on a Java web application where the framework insists that everything is Serializable. I assume that this isn't specific to the framework but to web applications in Java in general and my question is: what is the framework / server / whatever doing that is serializing things? Does it have to do it?I've been working on a Java web application whe