SQL JPA - Multiple columns as primary key

Question

If i want severeal Column to make up an ID.

SQL example :

CONSTRAINT [PK_NAME] PRIMARY KEY ([Column1],[Column2],[Column3])

How can

Answer 1

If all fields in the class are part of primary key, then solution would be pretty simple (extending solution provided by @raul-cuth):

@Entity
@IdClass(EntityExample.class)
public class EntityExample implements Serializable {

    @Id
    private int column1;

    @Id
    private int column2;

    @Id
    private int column3;
}