Example of @MapKeyTemporal in Hibernate

 @MapKeyTemporal(TemporalType.TIMESTAMP)
 

 package com.concretepage.persistence;

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

import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.MapKeyTemporal;
import javax.persistence.OneToMany;
import javax.persistence.TemporalType;

@Entity
public class Country implements Serializable {
	private static final long serialVersionUID = 1L;
	@Id
	@Column(name="id")
	private int id;
	
	@Column(name="name")
	private String name;
	
	@OneToMany(cascade=CascadeType.ALL)	
	@JoinColumn(name="country_id")
	@MapKeyTemporal(TemporalType.TIMESTAMP)
	private Map<Calendar,State> states;
	
	public Country(int id,String name,Map<Calendar,State> states){
		this.id=id;
		this.name=name;
		this.states=states;
	}
	public Country(){
	}
	public int getId() {
		return id;
	}
	public void setId(int id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Map<Calendar,State> getStates() {
		return states;
	}
	public void setStates(Map<Calendar,State> states) {
		this.states = states;
	}
}
 

package com.concretepage.persistence;
import java.io.Serializable;
import java.util.Calendar;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Id;
import javax.persistence.MapKeyTemporal;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;

@Entity
@Table(name = "state")
public class State  implements Serializable{
	private static final long serialVersionUID = 1L;

	@Id
	@Column(name = "id")
	private int id;

	@Id
	@Column(name = "country_id")
	private int countryId;
			
	@Column(name = "name") 
	private String name;
	
	@Temporal(TemporalType.TIMESTAMP)
	@Column(name="create_date")
	private Calendar createDate;
	
	public State(int id,int countryId,String name,Calendar createDate){
		this.id=id;
		this.countryId=countryId;
		this.name= name;
		this.createDate=createDate;
	}
	public State(){}
	
	public int getId() {
		return id;
	}

	public void setId(int id) {
		this.id = id;
	}
	public int getCountryId() {
		return countryId;
	}
	public void setCountryId(int countryId) {
		this.countryId = countryId;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
}
 

package com.concretepage.util;
import java.util.Calendar;
import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;
import java.util.Properties;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.AnnotationConfiguration;
import com.concretepage.persistence.Country;
import com.concretepage.persistence.State;
public class HibernateUtil {
	private static final SessionFactory concreteSessionFactory;
		static {
		 try {
				Properties prop= new Properties();
				prop.setProperty("hibernate.connection.url", "jdbc:mysql://localhost:3306/hibernate");
				prop.setProperty("hibernate.connection.username", "root");
				prop.setProperty("hibernate.connection.password", "");
				prop.setProperty("hibernate.hbm2ddl.auto", "update");
				prop.setProperty("dialect", "org.hibernate.dialect.MySQLDialect");
				
				concreteSessionFactory = new AnnotationConfiguration()
			   .addPackage("com.concretepage.persistence")
					   .addProperties(prop)
					   .addAnnotatedClass(Country.class)
					   .addAnnotatedClass(State.class)
					   .buildSessionFactory();
		  } catch (Throwable ex) {
			throw new ExceptionInInitializerError(ex);
		  }
		}
		public static Session getSession()
				throws HibernateException {
			return concreteSessionFactory.openSession();
		}
		
		public static void main(String... args){
			Session session=getSession();
	    	session.beginTransaction();
	    	
	    	Calendar calendar = Calendar.getInstance();
	    	Map<Calendar, State> map= new HashMap<Calendar,State>();
	    	calendar.add(Calendar.YEAR,-50);
	    	State s1= new State(1,1,"UP",calendar);
	    	map.put(calendar, s1);
	    	
	    	calendar.add(Calendar.DAY_OF_MONTH,-10);
	    	State s2= new State(2,1,"MP",calendar);
	    	map.put(calendar, s2);
	    	
	    	calendar.add(Calendar.DAY_OF_MONTH,-10);
	    	State s3= new State(3,1,"HP",calendar);
	    	map.put(calendar, s3);
	    		    		    
	    	Country c= new Country(1, "India", map);
	    	
	    	session.persist(c);
	    	session.getTransaction().commit();
	    	
	    	Country cval=(Country)session.get(Country.class, new Integer(1));
	    	Map<Calendar,State> states = cval.getStates();
	    	Iterator entries = states.entrySet().iterator();
	    	while (entries.hasNext()) {
	    	    Map.Entry entry = (Map.Entry) entries.next();
	    	    Calendar key = (Calendar)entry.getKey();
	    	    State value = (State)entry.getValue();
	    	    System.out.println("Key = " + key.getTimeInMillis() + ", Value = " + value.getName());
	    	}
	    	
	    	session.close();
	   }
	}