JPA Entity Manager Details | How we can make the id field of the string type a primary key?
How we can make the id field of the string type a primary key? Entity id @Id @GeneratedValue (strategy = GenerationType. IDENTITY ) private String id ; Trying to save Student student = new Student() ; student.setId( "tetasasa" ) ; student.setName( "Peter Smith" ) ; student.setEmail( "peter.smith@gmail.com" ) ; student.setAddress( "New York, USA" ) ; student.setPhone( "123456-2111" ) ; studentRepository .save(student) ; Error Caused by: org.hibernate.PersistentObjectException: detached entity passed to persist: org.example.entities.Student Solution @Id @GeneratedValue(generator="system-uuid") @GenericGenerator(name="system-uuid", strategy = "uuid") private String id; For more details about id generation please refer this - https://thorben-janssen.com/jpa-generate-primary-keys/