Advanced · 3–4 weeks
Banking Transaction System with ACID Guarantees
Accounts, transfers, double-entry ledger, and balance inquiries. Enforce ACID transfers with pessimistic locking, prevent overdrafts, and maintain immutable transaction log.
Why this project
Financial correctness is the ultimate test of transaction understanding. Interviewers will drill on isolation levels and locking.
Tech stack
Java 17Spring Boot 3PostgreSQL@TransactionalPessimistic lockingFlyway
Skills demonstrated
- ACID transactions
- Double-entry ledger
- Concurrency control
- Audit immutability
Interview talking points
- Isolation level choice and why
- Double-entry vs single balance column
- Handling transfer between accounts deadlock
- Reconciliation job design
Problem statement
Accounts, transfers, double-entry ledger, and balance inquiries. Enforce ACID transfers with pessimistic locking, prevent overdrafts, and maintain immutable transaction log.