Java partial (de)serialization of objects

Question

Let\'s say we have 3 Classes:

class foo { // not a singleton
    String s;
}
class bar {
    foo f;
    int i;
}
class baz {
    foo sameF;
}

Answer 1

If you want more controll you could overwrite writeObject() and readObject() and serialize yourself.

class bar {
    ...

    private void writeObject(ObjectOutputStream stream) throws IOException {
      // let version 1, later when you need to have versioning. 
      stream.writeInt(version);
      stream.writeInt(i);
      // leave out 
      // stream.writeObject(foo);

    }
}
// read object the analog, see 

http://docs.oracle.com/javase/6/docs/platform/serialization/spec/output.html#861

Answer 2

Mark references you don't want serialized with transient keyword.

Answer 3

You can make foo transient as below.

class bar {
    transient foo f;
    int i;
}