Ajax中定义是什么呀?

Java代码如下

Book.java
@Entity
@Table(="book")
public class Book{
private Longid,
private String title;
private String author;
private String language;
private String published;
private String sales:
public Stringgettn=(){  return title:}
public voidset  (String title)( this.title=title; }
public String     0{ return author;}
public void     (String, author) (
this.author=author.
public String       10​return language;)
public void      (String language){
this.language=language.
public B​00                   public String       10​return published: )
public void      (Stringpublished)(
@GeneratedValue(nerato="increment")      this.published=published.
GenericGenerator(​="increment".   {
-"increment")