serialization - Java Serialised object vs Non serialised object

Question

1) Can a non-serialised java object be sent over the network to be executed by another JVM or stored in local file storage to get the data restored? 2) What is the difference between serialising and storing the java object vs storing the java object without serialising it?

Answer 1

Serialization is a way to represent a java object as a series of bytes. Its just a format nothing more. A "build-in" java serialization is a class that provides an API for conversion of the java object to a series of bytes. That's it. Of course, deserialization is a "complementary" process that allows to convert this binary stream back to the object.

The serialization/deserialization itself has nothing to do with the "sending over the network" thing. Its just convenient to send a binary stream that can be created from the object with the serialization.

Even more, sometimes the built-in serialization is not an optimal way to get the binary stream, because sometimes the object can be converted by using less bytes.

So you can use you're custom protocol, provide your own customization for serialization (for example, Externalizable)

or even use third party libraries like Apache Avro

I think this effectively answers both of your questions:

1. You can turn the non-serialized object (I guess the one that doesn't implement "Serializable" interface) to the series of bytes (byte stream) by yourself if you want and then send it over the network, store in a binary file, whatsoever. Of course you'll have to understand how to read this binary format for converting back.

2. Since serialization is just a protocol of conversion and not a "storage related thing", the answer is obvious.

Hope this helps.