The Java EE 5 Tutorial

Creating an Entity Class

As explained in Accessing Databases from Web Applications, an entity class is a component that represents a table in the database. In the case of the Duke’s Bookstore application, there is only one database table and therefore only one entity class: the Book class.

The Book class contains properties for accessing each piece of data for a particular book, such as the book’s title and author. To make it an entity class that is accessible to an entity manager, you need to do the following:

The following code shows part of the Book class:

import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.Table;


public class Book implements Serializable {

    private String bookId;
    private String title;

    public Book() { }

    public Book(String bookId, String title, ...) {
        this.bookId = bookId;
        this.title = title;

    public String getBookId() {
        return this.bookId;

    public String getTitle() {
        return this.title;

    public void setBookId(String id) {

    public void setTitle(String title) {