Serialization

Serialization in Java is a mechanism of writing the state of an object into a byte stream. This tutorial will teach you how to serialize and deserialize objects.

Serializing an Object

To serialize an object, use the ObjectOutputStream class:

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.io.Serializable;

class Person implements Serializable {
    private static final long serialVersionUID = 1L;
    String name;
    int age;
    
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
}

public class Main {
    public static void main(String[] args) {
        Person person = new Person("Alice", 30);
        try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream("person.ser"))) {
            oos.writeObject(person);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}
      

Deserializing an Object

To deserialize an object, use the ObjectInputStream class:

import java.io.FileInputStream;
import java.io.IOException;
import java.io.ObjectInputStream;

public class Main {
    public static void main(String[] args) {
        try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream("person.ser"))) {
            Person person = (Person) ois.readObject();
            System.out.println("Name: " + person.name);
            System.out.println("Age: " + person.age);
        } catch (IOException | ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
}
      

Transient Keyword

The transient keyword in Java is used to indicate that a field should not be serialized:

class Person implements Serializable {
    private static final long serialVersionUID = 1L;
    String name;
    transient int age; // This field will not be serialized
    
    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
}
      

In this example, the age field will not be serialized because it is marked as transient.

Continue exploring our intermediate tutorials to learn more about Java programming.