Serialization and Deserialization

File handling in Java allows you to perform various operations on files, including serialization and deserialization. Serialization is the process of converting objects into a byte stream, while deserialization is the process of reconstructing objects from a byte stream. This can be particularly useful when you want to store Java objects persistently or send them across a network.

1. Serialization:

Serialization Example:

import java.io.*;

class Student implements Serializable {
    private String name;
    private int rollNumber;

    public Student(String name, int rollNumber) {
        this.name = name;
        this.rollNumber = rollNumber;
    }

    public void display() {
        System.out.println("Name: " + name);
        System.out.println("Roll Number: " + rollNumber);
    }
}

public class SerializationExample {
    public static void main(String[] args) {
        Student student = new Student("Alice", 123);

        try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("student.ser"))) {
            oos.writeObject(student);
            System.out.println("Object serialized successfully.");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

In this example, a Student object is serialized and saved into a file named "student.ser". The ObjectOutputStream class is used to write the object to the file. The Student class implements Serializable.

2. Deserialization:

Deserialization Example:

import java.io.*;

class Student implements Serializable {
    private String name;
    private int rollNumber;

    public Student(String name, int rollNumber) {
        this.name = name;
        this.rollNumber = rollNumber;
    }

    public void display() {
        System.out.println("Name: " + name);
        System.out.println("Roll Number: " + rollNumber);
    }
}

public class DeserializationExample {
    public static void main(String[] args) {
        try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream("student.ser"))) {
            Student student = (Student) ois.readObject();
            student.display();
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}

In this example, the Student object is deserialized from the "student.ser" file using the ObjectInputStream class. The object is cast back to the Student class, and its display() method is called.

Explanation:

• Serialization:

  • ObjectOutputStream is used to serialize objects. It writes primitive data types and graphs of Java objects to an OutputStream.

  • The class to be serialized (Student in this case) implements the Serializable interface, which is a marker interface indicating the class is serializable.

  • Serialized objects can be saved to a file for future use or transmitted over a network.

• Deserialization:

  • ObjectInputStream is used for deserialization. It reads objects from an InputStream and deserializes them.

  • The class being deserialized must have the same serialVersionUID as the class that was serialized.

  • The deserialized object can be cast back to its original class for further use.

Remember to handle IOException and ClassNotFoundException to ensure your file handling, serialization, and deserialization operations are error-free and robust.