package elvis.entity; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.OneToOne; @Entity public class Student { @Id @GeneratedValue() private int id; private String name; @OneToOne private Diploma diploma; public Student() { } public Student(String name) { this.name = name; } public void setDiploma(Diploma diploma) { this.diploma = diploma; } public Diploma getDiploma() { return diploma; } public String toString() { return "Student[id=" + id + ",name=" + name + ",diploma=" + (diploma == null ? "null" : "@" + diploma.hashCode()) + "]"; } }