This is a console-based train booking system made in Java from scratch. I started building this project while learning Java itself so this app became my way of learning the language, exploring concepts like object-oriented programming, file handling, and basic service structures.

I started with just one idea: can I build a working train booking app without any database, using only Java?

At first, I didn't know how to structure things. Slowly, I began learning:

• how to organize code into services and entities
• how to read/write JSON files using Jackson
• how to hash passwords securely using BCrypt
• how to manage data like trains, seats, users, and tickets through logic

While building this, I not only understood Java syntax, but also real-world application flow signup, login, storing state, and reading/updating files.

• User Signup with password hashing
• User Login and validation
• Train search by source and destination
• Seat selection using 2D seat matrix
• Ticket booking with train, date, source/destination
• Fetching booked tickets per user
• Cancel ticket by ID
• All data stored in local JSON files (no DB used)

• Java 20
• Gradle (build tool)
• Jackson (for JSON parsing)
• BCrypt (for password hashing)
• Local storage using users.json and trains.json

ticket_booking/
├── Entities/         User, Ticket, Train
├── Services/         Business logic for train & booking
├── localDb/          All data stored here in JSON files
├── util/             Password hashing utility
└── App.java          Main entry point for the system

1. Make sure Java 20 is installed
2. Open terminal and run:

./gradlew run

Low level design is the most important part of a project.
While building this, I realized that how you structure your classes, services, and data flow matters way more than just writing logic that "works".

This one project helped me understand:

• Java objects and class-based structure
• File I/O and persistence without a DB
• Writing modular code using services
• Cleanly separating UI logic and backend logic
• Using external libraries with Gradle

This was my first full project in Java and I'm proud of it. It's not perfect, but it works end-to-end. Now that the system is finally working, I understand both Java syntax and how to build real applications.