fetchtype hibernate annotation

//Address.java

package com.hibernate.model;

import javax.persistence.Column;

import javax.persistence.Embeddable;

@Embeddable

public class Address {

      @Column(name = "STREET_NAME")

      private String street;

      @Column(name = "CITY_NAME")

      private String city;

      @Column(name = "DISTRICT_NAME")

      private String district;

      @Column(name = "COUNTRY_NAME")

      private String country;

      @Column(name = "POSTAL_CODE")

      private Integer postalcode;

      public String getStreet() {

            return street;

      }

      public void setStreet(String street) {

            this.street = street;

      }

      public String getCity() {

            return city;

      }

      public void setCity(String city) {

            this.city = city;

      }

      public String getDistrict() {

            return district;

      }

      public void setDistrict(String district) {

            this.district = district;

      }

      public String getCountry() {

            return country;

      }

      public void setCountry(String country) {

            this.country = country;

      }

      public Integer getPostalcode() {

            return postalcode;

      }

      public void setPostalcode(Integer postalcode) {

            this.postalcode = postalcode;

      }

}

UserDetails.java

package com.hibernate.model;

import java.util.ArrayList;

import java.util.Collection;

import javax.persistence.ElementCollection;

import javax.persistence.Entity;

import javax.persistence.FetchType;

import javax.persistence.GeneratedValue;

import javax.persistence.Id;

import javax.persistence.JoinColumn;

import javax.persistence.JoinTable;

import javax.persistence.Table;

@Entity

@Table(name = "userdetails")

public class UserDetails {

      @Id

      @GeneratedValue

      private Integer userId;

      private String userName;

      @ElementCollection(fetch=FetchType.EAGER)

      @JoinTable(name="USER_ADDRESS",joinColumns=@JoinColumn(name="USER_ID"))

      private Collection<Address> listOfAddresses = new ArrayList<Address>();

     

      public Collection<Address> getListOfAddresses() {

            return listOfAddresses;

      }

      public void setListOfAddresses(Collection<Address> listOfAddresses) {

            this.listOfAddresses = listOfAddresses;

      }

      public Integer getUserId() {

            return userId;

      }

      public void setUserId(Integer userId) {

            this.userId = userId;

      }

      public String getUserName() {

            return userName;

      }

      public void setUserName(String userName) {

            this.userName = userName;

      }

}

UserAccess.java

package com.hibernate;

import org.hibernate.Session;

import org.hibernate.SessionFactory;

import org.hibernate.cfg.Configuration;

import com.hibernate.model.Address;

import com.hibernate.model.UserDetails;

public class UserAccess {

      public static void main(String[] args) {

            // TODO Auto-generated method stub

            UserDetails user = new UserDetails();

            user.setUserName("karthik reddy");

            Address address1 = new Address();

            address1.setStreet("A");

            address1.setCity("Irala");

            address1.setDistrict("Chittoor");

            address1.setCountry("India");

            address1.setPostalcode(517130);

           

            Address address2 = new Address();

            address2.setStreet("B");

            address2.setCity("Kanipakam");

            address2.setDistrict("Chittoor1");

            address2.setCountry("India");

            address2.setPostalcode(517135);

           

            user.getListOfAddresses().add(address1);

            user.getListOfAddresses().add(address2);

            SessionFactory factory = new Configuration().configure()

                        .buildSessionFactory();

            Session session = factory.openSession();

            session.beginTransaction();

        session.save(user);

            session.getTransaction().commit();

            session.close();

            user=null;

            session=factory.openSession();

            user=(UserDetails)session.get(UserDetails.class,1);

            session.close();

            System.out.println(user.getListOfAddresses().size());

          factory.close();

      }

}

hibernate.cfg.xml  

     same a previous program

If we run the above application we will get error because of lazy loading  the error is

Hibernate: select hibernate_sequence.nextval from dual

Hibernate: insert into userdetails (userName, userId) values (?, ?)

Hibernate: insert into USER_ADDRESS (USER_ID, CITY_NAME, COUNTRY_NAME, DISTRICT_NAME, POSTAL_CODE, STREET_NAME) values (?, ?, ?, ?, ?, ?)

Hibernate: insert into USER_ADDRESS (USER_ID, CITY_NAME, COUNTRY_NAME, DISTRICT_NAME, POSTAL_CODE, STREET_NAME) values (?, ?, ?, ?, ?, ?)

Hibernate: select userdetail0_.userId as userId0_0_, userdetail0_.userName as userName0_0_ from userdetails userdetail0_ where userdetail0_.userId=?

Exception in thread "main" org.hibernate.LazyInitializationException: failed to lazily initialize a collection of role: com.hibernate.model.UserDetails.listOfAddresses, no session or session was closed

      at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationException(AbstractPersistentCollection.java:383)

      at org.hibernate.collection.AbstractPersistentCollection.throwLazyInitializationExceptionIfNotConnected(AbstractPersistentCollection.java:375)

      at org.hibernate.collection.AbstractPersistentCollection.readSize(AbstractPersistentCollection.java:122)

      at org.hibernate.collection.PersistentBag.size(PersistentBag.java:248)

      at com.hibernate.UserAccess.main(UserAccess.java:43)

To rectify we have 2 options 

remove the session.close() 

         or

@ElementCollection(fetch=FetchType.EAGER)----->change this in UserDetails.java

Output:

Hibernate: select hibernate_sequence.nextval from dual

Hibernate: insert into userdetails (userName, userId) values (?, ?)

Hibernate: insert into USER_ADDRESS (USER_ID, CITY_NAME, COUNTRY_NAME, DISTRICT_NAME, POSTAL_CODE, STREET_NAME) values (?, ?, ?, ?, ?, ?)

Hibernate: insert into USER_ADDRESS (USER_ID, CITY_NAME, COUNTRY_NAME, DISTRICT_NAME, POSTAL_CODE, STREET_NAME) values (?, ?, ?, ?, ?, ?)

Hibernate: select userdetail0_.userId as userId0_0_, userdetail0_.userName as userName0_0_, listofaddr1_.USER_ID as USER1_0_2_, listofaddr1_.CITY_NAME as CITY2_2_, listofaddr1_.COUNTRY_NAME as COUNTRY3_2_, listofaddr1_.DISTRICT_NAME as DISTRICT4_2_, listofaddr1_.POSTAL_CODE as POSTAL5_2_, listofaddr1_.STREET_NAME as STREET6_2_ from userdetails userdetail0_, USER_ADDRESS listofaddr1_ where userdetail0_.userId=listofaddr1_.USER_ID(+) and userdetail0_.userId=?

2