What is the significance of the @Embeddable annotation in the context of JPA and how is it used?

The @Embeddable annotation in JPA is used to designate a class whose objects can be embedded into other entities as part of their state. Such a class does not have its own identifier and does not exist separately in the database.

This is convenient for grouping related fields into a separate class, which is then included in an entity using the @Embedded annotation.

Example:

@Embeddable
public class Address {
    private String street;
    private String city;
    private String zipCode;
    // getters and setters
}

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

    @Embedded
    private Address address;
    // other fields
}

Thus, the Address fields will be stored in the User table as columns, not in a separate table.