1. public class Foo implements java.io.Serializable {2.   private int x;3.   public int getX() { return x; }4.  publicFoo(int x){this.x=x; }5.   private void writeObject( ObjectOutputStream s)6.   throws IOException {7.    /* insert code here*/8.   }9. }
s.writeInt(x);
s.serialize(x);
s.writeObject(x);
s.defaultWriteObject();