title: Serialization Java: which classes need to "implement Serializable"?
body: <p>so I know I could probably figure it out eventually, but I couldn't really find a topic that answers this seemingly simple question.</p>
  
  <p>I am serializing a vector of a set of objects, with each such object pertaining to one user-defined class.  I know vectors are serializable.  Do I also have to make the user-defined class implement serializable?  And, each of these user-defined classes contains other user-defined classes.  Do those have to be labeled as implementing Serializable as well?  (and so on, or do just the top-level class need to implement Serializable)?</p>
  
  <p>(Forget noting that arrayLists should be used instead of vectors, I've heard that before, I'm practicing because I hear vectors are good for multithreading.  I found topics that discuss similar stuff, but not precisely this)</p>
  
  <p>Thanks</p>