Could you explain the mechanism of ORM functioning in the context of JPA?

ORM (Object-Relational Mapping) in the context of JPA (Java Persistence API) is a mechanism that allows working with a database through Java objects rather than directly through SQL queries.

JPA provides a standard interface for mapping Java classes to database tables. Specifically:

• Entity classes are annotated (@Entity), and fields are linked to table columns.
• JPA automatically generates SQL queries for CRUD operations (create, read, update, delete).
• It manages the state of objects (new, managed, detached, removed).
• It allows using JPQL — an object-oriented query language.

Example of an entity:

@Entity
public class User {
    @Id
    @GeneratedValue
    private Long id;

    private String name;

    // getters and setters
}

Thus, ORM via JPA simplifies database work by hiding SQL details and allowing work with familiar objects.