Public class MyBean implements java.io.Serializable
{
  private voide writeObject(ObjectOutputStream s)
    throws IOException
  {
    s.defaultWriteObject();
    s.writeString("SomeData");
  }
  private viod readObject(ObjectInputStrean s)
    throws ClassNotFoundException, IOException
  {
    s.defaultReadObject();
    if (!"SomeData".equals(s.readString())
      throw IOException("Can't find SomeData");
  }