Object Serialization and Deserialization for Java Client-Server Interaction

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Recently, we were tasked with developing a chat application using Java sockets. As part of the assignment, we were encouraged not to use WebSockets as they facilitate many features. However, the purpose of this project is to learn the basics and apply theoretical knowledge from scratch. As we delve into our search, we encounter these two concepts

Serialization and deserialization are techniques used to convert objects into a format that can be easily transferred over a network (serialization) and reconstructed at the other end (deserialization).

In the context of a Client-Server application using sockets in Java, this allows for transferring Java objects between the client and the server.

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Here’s how you can set up serialization/deserialization of data in your application:

1. Define Serializable classes:
For objects to be serialized/deserialized, the corresponding classes need to implement the `Serializable` interface.

import java.io.Serializable;
public class Message implements Serializable {
 private String content;
 private String sender;
 // other attributes, constructors, getters, setters, etc.
 }

2. Serialization of objects on the client side:
When the client wants to send an object to the server, it converts the object into a stream of bytes using serialization.
This can be done by writing the object to an output stream like, an ObjectOutputStream connected to the socket.

ObjectOutputStream out = new ObjectOutputStream(socket.getOutputStream());
Message message = new Message("Hello", "Alice");
out.writeObject(message);

3. Deserialization of objects on the server side:
The server receives the bytes from the socket and converts them back into an object using deserialization.
This can be done by reading the object from an input stream like an ObjectInputStream connected to the socket.

ObjectInputStream in = new ObjectInputStream(socket.getInputStream());
Message receivedMessage = (Message) in.readObject();

4. Repeat the process for other types of objects:
You can serialize and deserialize different types of objects by following the same process as described above for each type of object you want to transfer between the client and the server.

Make sure to handle exceptions related to serialization/deserialization, such as IOException and ClassNotFoundException, which may occur when writing or reading objects.

By using these techniques, you can seamlessly transfer Java objects between the client and the server in your messaging application. This enabes communication and sharing of complex data.