What are the main approaches to creating unique identifiers when working with Hibernate?

When working with Hibernate to create unique entity identifiers, various ID generation strategies are used. The main approaches:

1. AUTO — Hibernate automatically selects the strategy based on the database.

2. IDENTITY — the database itself generates a unique identifier, for example, using auto-increment.

3. SEQUENCE — a database sequence is used (for example, in Oracle or PostgreSQL).

4. TABLE — unique values are stored in a special table, ensuring portability.

5. UUID — generation of unique identifiers in UUID format, which is convenient for distributed systems.

Example of using an annotation for ID generation:

@Entity
public class User {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    // other fields
}

The choice of strategy depends on performance requirements, portability, and database features.