@Entity
@Table(name="books")
public class Book implements Serializable {
	
	@Id
	@GeneratedValue(strategy=IDENTITY)
	@Column(name="book_id")
	private int bookId;

//bi-directional many-to-many association to Author
	@ManyToMany(fetch = EAGER, cascade = { MERGE, DETACH, REFRESH, PERSIST })
	@JoinTable(name = "authors_books", joinColumns = { @JoinColumn(name = "book_id") }, 
	inverseJoinColumns = { @JoinColumn(name = "author_id") })	
private List<Author> authors = new ArrayList<Author>();
.
.
.

@Entity
@Table(name = "authors")
public class Author implements Serializable
{
	
	@Id
	@GeneratedValue(strategy = IDENTITY)
	@Column(name = "author_id")
	private int authorId;
@Column(unique = true)
	private String name;

	// bi-directional many-to-many association to Book
	@ManyToMany(fetch = EAGER, mappedBy = "authors", cascade = { MERGE, REFRESH, DETACH })
	private List<Book> books;
.
.
.

@Stateless

public class BookServiceBean {
       
public Book create(Book entity)
	{		
		getEntityManager().persist(entity);
		return entity;
	}
.
.
.
}

....
Book book = new Book();
		book.setTitle("Title");
		book.setFileSize(10);
		book.setPagesCount(400);
		book.setPicture("pic" + rnd.nextInt(50) + ".jpg");
		book.setYear(2007 + rnd.nextInt(6));
		book.setDescription("Description");
		book.addAuthor(new Author("Joe Smith"));
		book.addAuthor(new Author("Randall Osborn"));

getEntityManager().persist(book);

        @Id
	@GeneratedValue(strategy = IDENTITY)
	@Column(name = "author_id")
	private int authorId;

INSERT INTO authors_books (author_id, book_id) VALUES ($author_id, $book_id)