@Entity @Table(name="BOOK")
public class Book {
    @Id @Column(name="BOOK_ID")
    private Long id;
	@Column
	private String title;
	@ManyToOne
	@JoinColumn(name = "AUTHOR_ID")
	private Author author;
}

@Entity @Table(name = "AUTHOR")
public class Author {
    @Id @Column(name = "AUTHOR_ID")
    private Long id;
	@Column
	private String name;
	@Column
	private Date birthDate;
	@OneToMany(mappedBy = "author")
	private List<Book> books;
}