Meyyappan has posted 101 posts at DZone. View Full User Profile

Hibernate Many-To-Many Mapping Using Annotations Tutorial

  • submit to reddit

In this example you will learn how to map many-to-many relationship using Hibernate Annotations. Consider the following relationship between Student and Course entity.

According to the relationship a student can enroll in any number of courses and the course can have any number of students.

To create this relationship you need to have a STUDENT, COURSE and STUDENT_COURSE table. The relational model is shown below.

To create the STUDENT, COURSE and STUDENT_COURSE table you need to create the following Java Class files.

Student class is used to create the STUDENT and STUDENT_COURSE table.

package com.vaannila.student;

import java.util.HashSet;
import java.util.Set;

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.Table;

@Table(name = "STUDENT")
public class Student {

	private long studentId;
	private String studentName;
	private Set<Course> courses = new HashSet<Course>(0);

	public Student() {

	public Student(String studentName) {
		this.studentName = studentName;

	public Student(String studentName, Set<Course> courses) {
		this.studentName = studentName; = courses;

	@Column(name = "STUDENT_ID")
	public long getStudentId() {
		return this.studentId;

	public void setStudentId(long studentId) {
		this.studentId = studentId;

	@Column(name = "STUDENT_NAME", nullable = false, length = 100)
	public String getStudentName() {
		return this.studentName;

	public void setStudentName(String studentName) {
		this.studentName = studentName;

	@ManyToMany(cascade = CascadeType.ALL)
	@JoinTable(name = "STUDENT_COURSE", joinColumns = { @JoinColumn(name = "STUDENT_ID") }, inverseJoinColumns = { @JoinColumn(name = "COURSE_ID") })
	public Set<Course> getCourses() {

	public void setCourses(Set<Course> courses) { = courses;


The @ManyToMany annotation is used to create the many-to-many relationship between the Student and Course entities. The @JoinTable annotation is used to create the STUDENT_COURSE link table and @JoinColumn annotation is used to refer the linking columns in both the tables.

Course class is used to create the COURSE table.

package com.vaannila.student;

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

public class Course {

	private long courseId;
	private String courseName;

	public Course() {

	public Course(String courseName) {
		this.courseName = courseName;

	public long getCourseId() {
		return this.courseId;

	public void setCourseId(long courseId) {
		this.courseId = courseId;

	@Column(name="COURSE_NAME", nullable=false)
	public String getCourseName() {
		return this.courseName;

	public void setCourseName(String courseName) {
		this.courseName = courseName;


Now create the hibernate configuration file with the Student and Course class mapping.

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC
		"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
        <property name="hibernate.connection.driver_class"> org.hsqldb.jdbcDriver</property>
        <property name="hibernate.connection.url"> jdbc:hsqldb:hsql://localhost</property>
        <property name="hibernate.connection.username">sa</property>
        <property name="connection.password"></property>
        <property name="connection.pool_size">1</property>
        <property name="hibernate.dialect"> org.hibernate.dialect.HSQLDialect</property>
        <property name="show_sql">true</property>
        <property name="">create-drop</property>
        <mapping class="com.vaannila.student.Student" />
        <mapping class="com.vaannila.student.Course" />

Create the Main class to run the example.

package com.vaannila.student;

import java.util.HashSet;
import java.util.Set;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;

import com.vaannila.util.HibernateUtil;

public class Main {

	public static void main(String[] args) {

		Session session = HibernateUtil.getSessionFactory().openSession();
		Transaction transaction = null;
		try {
			transaction = session.beginTransaction();

			Set<Course> courses = new HashSet<Course>();
			courses.add(new Course("Maths"));
			courses.add(new Course("Computer Science"));

			Student student1 = new Student("Eswar", courses);
			Student student2 = new Student("Joe", courses);;;

		} catch (HibernateException e) {
		} finally {


On executing the Main class you will see the following output.

The STUDENT table has two records.

The COURSE table has two records.

The STUDENT_COURSE table has four records to link the student and courses.

Each student has enrolled in the same two courses, this illustrates the many-to-many mapping.

The folder structure of the example is shown below.


You can download the source code of this example here.

Source :Download
Published at DZone with permission of its author, Meyyappan Muthuraman.

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)



Dan Rios replied on Wed, 2013/02/13 - 12:53am

Mark Arsenault replied on Wed, 2013/12/25 - 11:45pm in response to: Dan Rios

Stop posting that rhetoric! 

Great tutorial!

Comment viewing options

Select your preferred way to display the comments and click "Save settings" to activate your changes.