JPA Map mapping

Question

How can I map a Map in JPA without using Hibernate\'s classes?

Answer 1

Suppose I have an entity named Book which is having a Map of chapters:

import java.io.Serializable;
import java.util.Map;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;    
import org.hibernate.annotations.CollectionOfElements;
import org.hibernate.annotations.MapKey;
@Entity
public class Book implements Serializable{
@Column(name="BOOK_ID")
@Id
@GeneratedValue(strategy=GenerationType.AUTO)
private Long bookId;    

@CollectionOfElements(targetElement=java.lang.String.class)
@JoinTable(name="BOOK_CHAPTER",
        joinColumns=@JoinColumn(name="BOOK_ID"))
@MapKey (columns=@Column(name="CHAPTER_KEY"))
@Column(name="CHAPTER")
private Map chapters;
public Long getBookId() {
    return bookId;
}
public void setBookId(Long bookId) {
    this.bookId = bookId;
}
public Map getChapters() {
    return chapters;
}
public void setChapters(Map chapters) {
    this.chapters = chapters;
}               

}

It works for me.