Object Serialization with Serializable, ObjectOutputStream, and transient Keyword0%

Project 1: Bank Account Management System with Polymorphism and Serialization

Object Serialization with Serializable, ObjectOutputStream, and transient Keyword

Intermediate13 min read•Updated: 2026-10-22

💾 Object Serialization and the transient Keyword

Introduction

Serialization converts an in-memory Java object into a binary byte stream to save to disk or transmit across a network. Deserialization reconstructs the byte stream back into a live object.

🛡️ The `Serializable` Marker Interface & `transient`

A class must implement java.io.Serializable to be saved.
Fields marked transient are skipped during serialization (used for passwords, sensitive data, or cached caches).

1import java.io.*;
2 
3class UserAccount implements Serializable {
4    @Serial
5    private static final long serialVersionUID = 1L; // Versioning ID
6 
7    private String username;
8    private transient String passwordHash; // Omitted from binary dump for security!
9 
10    public UserAccount(String user, String pass) {
11        this.username = user;
12        this.passwordHash = pass;
13    }
14 
15    @Override
16    public String toString() {
17        return "UserAccount[username=" + username + ", pass=" + passwordHash + "]";
18    }
19}
20 
21public class SerializationDemo {
22    public static void main(String[] args) throws Exception {
23        String filename = "account.ser";
24 
25        // Save object
26        try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(filename))) {
27            oos.writeObject(new UserAccount("sumit_admin", "SuperSecretSalt123"));
28        }
29 
30        // Restore object
31        try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(filename))) {
32            UserAccount restored = (UserAccount) ois.readObject();
33            System.out.println("Restored: " + restored); // Notice passwordHash restored as null!
34        }
35    }
36}

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Project 1: Bank Account Management System with Polymorphism and Serialization

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Modern Java NIO: java.nio.file.Path and java.nio.file.Files	Project 1: Bank Account Management System with Polymorphism and Serialization

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Project 1: Bank Account Management System with Polymorphism and Serialization

Object Serialization with Serializable, ObjectOutputStream, and transient Keyword

Intermediate13 min read•Updated: 2026-10-22

Study Materials

💾 Object Serialization and the transient Keyword

Introduction

Serialization converts an in-memory Java object into a binary byte stream to save to disk or transmit across a network. Deserialization reconstructs the byte stream back into a live object.

🛡️ The `Serializable` Marker Interface & `transient`

A class must implement java.io.Serializable to be saved.
Fields marked transient are skipped during serialization (used for passwords, sensitive data, or cached caches).

1import java.io.*;
2 
3class UserAccount implements Serializable {
4    @Serial
5    private static final long serialVersionUID = 1L; // Versioning ID
6 
7    private String username;
8    private transient String passwordHash; // Omitted from binary dump for security!
9 
10    public UserAccount(String user, String pass) {
11        this.username = user;
12        this.passwordHash = pass;
13    }
14 
15    @Override
16    public String toString() {
17        return "UserAccount[username=" + username + ", pass=" + passwordHash + "]";
18    }
19}
20 
21public class SerializationDemo {
22    public static void main(String[] args) throws Exception {
23        String filename = "account.ser";
24 
25        // Save object
26        try (ObjectOutputStream oos = new ObjectOutputStream(new FileOutputStream(filename))) {
27            oos.writeObject(new UserAccount("sumit_admin", "SuperSecretSalt123"));
28        }
29 
30        // Restore object
31        try (ObjectInputStream ois = new ObjectInputStream(new FileInputStream(filename))) {
32            UserAccount restored = (UserAccount) ois.readObject();
33            System.out.println("Restored: " + restored); // Notice passwordHash restored as null!
34        }
35    }
36}

Next Lesson

Project 1: Bank Account Management System with Polymorphism and Serialization

Continue learning with hands-on practice, examples, and exercises in the upcoming topic.

Related Lessons

Previous Lesson	Next Lesson
Modern Java NIO: java.nio.file.Path and java.nio.file.Files	Project 1: Bank Account Management System with Polymorphism and Serialization

Practice Quiz

Test your understanding of this lesson with 1 questions. Each question has one correct answer.

Previous Next

💾 Object Serialization and the transient Keyword

Introduction

🛡️ The Serializable Marker Interface & transient

Project 1: Bank Account Management System with Polymorphism and Serialization

Related Lessons

Practice Quiz

Loading Page Content...

💾 Object Serialization and the transient Keyword

Introduction

🛡️ The Serializable Marker Interface & transient

Project 1: Bank Account Management System with Polymorphism and Serialization

Related Lessons

Practice Quiz

🛡️ The `Serializable` Marker Interface & `transient`

🛡️ The `Serializable` Marker Interface & `transient`