title: Why do transfer objects need to implement Serializable?
body: <p>I realized today that I have blindly just followed this requirement for years without ever really asking why.  Today, I ran across a NotSerializableException with a model object I created from scratch and I realized enough is enough.</p>
  
  <p>I was told this was because of session replication between load-balanced servers, but I know I've seen other objects at session scope that do not implement Serializable.  Is this the real reason?</p>