Embeddable classes

Embeddable classes group the properties for Entity classes.

Embeddable definition

The following code snippet shows how to define an embeddable:

@Embeddable
public class Address {

    final String city;

    final String street;

    @Column(name = "ZIP_CODE")
    final String zip;

    public Address(String city, String street, String zip) {
        this.city = city;
        this.street = street;
        this.zip = zip;
    }
}

The embeddable class is used as the entity field type:

@Entity
public class Employee {
    @Id
    Integer id;

    Address address;
}

The above entity definition is equivalent to following one:

@Entity
public class Employee {
    @Id
    Integer id;

    String city;

    String street;

    @Column(name = "ZIP_CODE")
    String zip;
}

Note

In Java 14 and later version, you can annotate records with @Embeddable:

@Embeddable
public record Address(
  String city,
  String street,
  @Column(name = "ZIP_CODE")String zip) {
}

Naming convention

A naming convention is inherited from the enclosing Entity classes.

Field definition

By default, the fields are persistent and correspond to the database columns or result set columns.

The field type must be one of the following:

@Embeddable
public class Address {
    ...
    String street;
}

Column

You can specify the corresponding column name with the @Column annotation:

@Column(name = "ZIP_CODE")
final String zip;

Transient

If an embeddable has fields that you don’t want to persist, you can annotate them using @Transient:

Method definition

There are no limitations in the use of methods.

Example

Employee employee = new Employee(); // Entity
Address address = new Address("Tokyo", "Yaesu", "103-0028"); // Embeddable
employee.setAddress(address);