interface is implemented by classes that provide a mechanism
to serialize their state and recreate instances from a serialized form.
The only restriction on the serialized form is that it is a string. A class may change
its serialized form, however if it does so and wishes to maintain backwards compatibility
with current serialized forms, it will need the deserialize method to cope with multiple
different versions of serialized form. For this reason, it's good practice to put the
serialization version at the beginning of the serialized form.
It is not the responsibility of a Serializable class to include its classname in its