Java: What is the difference between @Transactional and @Version?

@Transactional — manages transactions. @Version — optimistic locking.

@Transactional:

• Defines transaction boundaries.
• Supports: REQUIRED, REQUIRES_NEW, etc.
• Rollback on exception.
• Manages ACID properties.

1@Service
2@Transactional
3public class UserService {
4    public void transferMoney(Long from, Long to, BigDecimal amount) {
5        // All in one transaction
6        debit(from, amount);
7        credit(to, amount);
8    }
9}

@Version:

• Optimistic locking.
• Prevents lost updates.
• Throws OptimisticLockException on conflict.
• Uses version column for conflict detection.

1@Entity
2public class User {
3    @Id
4    private Long id;
5
6    @Version
7    private Long version;
8
9    private String name;
10}

How it works:

1. @Transactional defines transaction boundaries (begin, commit, rollback).
2. @Version uses a version column to detect conflicts.
3. @Transactional ensures atomicity and consistency.
4. @Version prevents lost updates in concurrent environments.

Key difference:

• @Transactional — ACID transactions.
• @Version — optimistic concurrency control.

Best practice:

• Use @Transactional for transaction management.
• Use @Version for optimistic locking.
• Combine both for concurrent data access.