Dirty checking in hibernate example

In previous post Hibernate CRUD example in hibernate you learnt how to perform Create,Read,Update and Delete operation with database.In this post I will demonstrate about Dirty checking in hibernate example step by step using below project.

Technologies and tools used for this application are –

Hibernate 5.2.11.Final
Eclipse Mars.2 (4.5.0)
Maven 3.5.0
JavaSE 1.8
MySQL 5.5.57

Project Structure

Review the following project structure.

Step 1 – Create a maven project

Refer below link if you don’t know how to create Maven project in eclipse:
How to create Maven project

Step 2 – Add jar dependencies to pom.xml

below is the pom.xml file and add required Hibernate and MySQL connector dependencies to it.
pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.infotech</groupId>
  <artifactId>HibernateDirtyCheckingExample</artifactId>
  <version>0.0.1-SNAPSHOT</version>
   <properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
  </properties>

  <dependencies>
    <!-- MySQL connector dependency -->
    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
     <version>6.0.5</version>
    </dependency>
    
    <!-- Hibernate 5.2.11 Final dependency-->
    <dependency>
      <groupId>org.hibernate</groupId>
      <artifactId>hibernate-core</artifactId>
      <version>5.2.11.Final</version>
    </dependency>
  </dependencies>

  <build>
    <sourceDirectory>src/main/java</sourceDirectory>
    <plugins>
      <plugin>
        <artifactId>maven-compiler-plugin</artifactId>
        <version>3.5.1</version>
        <configuration>
          <source>1.8</source>
          <target>1.8</target>
        </configuration>
      </plugin>
    </plugins>
  </build>
</project>

<groupId>com.infotech</groupId>

<artifactId>HibernateDirtyCheckingExample</artifactId>

<version>0.0.1-SNAPSHOT</version>

<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>

</properties>

<groupId>mysql</groupId>

<artifactId>mysql-connector-java</artifactId>

</dependency>

<groupId>org.hibernate</groupId>

<artifactId>hibernate-core</artifactId>

<version>5.2.11.Final</version>

</dependency>

</dependencies>

<build>

<artifactId>maven-compiler-plugin</artifactId>

</configuration>

</plugin>

</plugins>

</build>

</project>

Step 3 – Create Entity class in hibernate

package com.infotech.entities;

import java.util.Date;

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

import org.hibernate.annotations.DynamicUpdate;

@Entity
@Table(name="employee_table")
@DynamicUpdate
public class Employee {

	@Id
	@Column(name="employee_id")
	@GeneratedValue(strategy=GenerationType.IDENTITY)
	private Integer employeeId;
	
	@Column(name="employee_name",length=100,nullable=false)
	private String employeeName;
	
	@Column(name="email",unique=true)
	private String email;
	
	@Column(name="date_of_joing")
	private Date doj;
	
	@Column(name="salary")
	private Double salary;
	
	public Integer getEmployeeId() {
		return employeeId;
	}
	public void setEmployeeId(Integer employeeId) {
		this.employeeId = employeeId;
	}
	public String getEmployeeName() {
		return employeeName;
	}
	public void setEmployeeName(String employeeName) {
		this.employeeName = employeeName;
	}
	public String getEmail() {
		return email;
	}
	public void setEmail(String email) {
		this.email = email;
	}
	public Date getDoj() {
		return doj;
	}
	public void setDoj(Date doj) {
		this.doj = doj;
	}
	public Double getSalary() {
		return salary;
	}
	public void setSalary(Double salary) {
		this.salary = salary;
	}
	@Override
	public String toString() {
		return "Employee [employeeId=" + employeeId + ", employeeName=" + employeeName + ", email=" + email + ", doj="
				+ doj + ", salary=" + salary + "]";
	}
}

package com.infotech.entities;

import java.util.Date;

import javax.persistence.Column;

import javax.persistence.Entity;

import javax.persistence.GeneratedValue;

import javax.persistence.GenerationType;

import javax.persistence.Id;

import javax.persistence.Table;

import org.hibernate.annotations.DynamicUpdate;

@Entity

@Table(name="employee_table")

@DynamicUpdate

public class Employee {

@Id

@Column(name="employee_id")

@GeneratedValue(strategy=GenerationType.IDENTITY)

private Integer employeeId;

@Column(name="employee_name",length=100,nullable=false)

private String employeeName;

@Column(name="email",unique=true)

private String email;

@Column(name="date_of_joing")

private Date doj;

@Column(name="salary")

private Double salary;

public Integer getEmployeeId() {

return employeeId;

}

public void setEmployeeId(Integer employeeId) {

this.employeeId = employeeId;

}

public String getEmployeeName() {

return employeeName;

}

public void setEmployeeName(String employeeName) {

this.employeeName = employeeName;

}

public String getEmail() {

return email;

}

public void setEmail(String email) {

this.email = email;

}

public Date getDoj() {

return doj;

}

public void setDoj(Date doj) {

this.doj = doj;

}

public Double getSalary() {

return salary;

}

public void setSalary(Double salary) {

this.salary = salary;

}

@Override

public String toString() {

return "Employee [employeeId=" + employeeId + ", employeeName=" + employeeName + ", email=" + email + ", doj="

+ doj + ", salary=" + salary + "]";

}

Step 4 – Create a Hibernate configuration file

Create an XML file named as hibernate.cfg.xml under src/main/resources folder and write the following code in it.
hibernate.cfg.xml

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>
	<session-factory>
	<property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>
		<property name="hibernate.connection.url">jdbc:mysql://localhost:4406/test</property>
		<property name="hibernate.connection.username">root</property>
		<property name="hibernate.connection.password">root</property>
		<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>
		<property name="hibernate.hbm2ddl.auto">update</property>
		<property name="hibernate.show_sql">true</property>
		<property name="hibernate.format_sql">true</property>
		
		<mapping class="com.infotech.entities.Employee"/>
	</session-factory>
</hibernate-configuration>

<?xml version='1.0' encoding='utf-8'?>

<!DOCTYPE hibernate-configuration PUBLIC

"-//Hibernate/Hibernate Configuration DTD//EN"

"http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">

<hibernate-configuration>

<session-factory>

<property name="hibernate.connection.driver_class">com.mysql.cj.jdbc.Driver</property>

<property name="hibernate.connection.url">jdbc:mysql://localhost:4406/test</property>

<property name="hibernate.dialect">org.hibernate.dialect.MySQL5Dialect</property>

<property name="hibernate.hbm2ddl.auto">update</property>

</session-factory>

</hibernate-configuration>

Step 5 – Hibernate utility class which is responsible to provide SessionFactory

package com.infotech.util;

import org.hibernate.SessionFactory;
import org.hibernate.boot.Metadata;
import org.hibernate.boot.MetadataSources;
import org.hibernate.boot.registry.StandardServiceRegistry;
import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

/**
 * @author kishan Kumar
 */
public class HibernateUtil {
  private static StandardServiceRegistry standardServiceRegistry;
  private static SessionFactory sessionFactory;

  static{
	    if (sessionFactory == null) {
	      try {
	        // Create StandardServiceRegistry
	        standardServiceRegistry = new StandardServiceRegistryBuilder()
	            .configure()
	            .build();
	        // Create MetadataSources
	        MetadataSources metadataSources = new MetadataSources(standardServiceRegistry);
	        // Create Metadata
	        Metadata metadata = metadataSources.getMetadataBuilder().build();
	        // Create SessionFactory
	        sessionFactory = metadata.getSessionFactoryBuilder().build();
	      } catch (Exception e) {
	        e.printStackTrace();
	        if (standardServiceRegistry != null) {
	          StandardServiceRegistryBuilder.destroy(standardServiceRegistry);
	        }
	      }
	    }
  }
  //Utility method to return SessionFactory
  public static SessionFactory getSessionFactory() {
	  return sessionFactory;
  }
}

package com.infotech.util;

import org.hibernate.SessionFactory;

import org.hibernate.boot.Metadata;

import org.hibernate.boot.MetadataSources;

import org.hibernate.boot.registry.StandardServiceRegistry;

import org.hibernate.boot.registry.StandardServiceRegistryBuilder;

/**

* @author kishan Kumar

public class HibernateUtil {

private static StandardServiceRegistry standardServiceRegistry;

private static SessionFactory sessionFactory;

static{

if (sessionFactory == null) {

try {

// Create StandardServiceRegistry

standardServiceRegistry = new StandardServiceRegistryBuilder()

.configure()

.build();

// Create MetadataSources

MetadataSources metadataSources = new MetadataSources(standardServiceRegistry);

// Create Metadata

Metadata metadata = metadataSources.getMetadataBuilder().build();

// Create SessionFactory

sessionFactory = metadata.getSessionFactoryBuilder().build();

} catch (Exception e) {

e.printStackTrace();

if (standardServiceRegistry != null) {

StandardServiceRegistryBuilder.destroy(standardServiceRegistry);

}

//Utility method to return SessionFactory

public static SessionFactory getSessionFactory() {

return sessionFactory;

}

Step 5 – Create two client classes

SavingEntityClientTest.java->This client class used to save entity object in database.
DirtyCheckingClientTest.java->This client class shows how dirty checks works in hibernate

package com.infotech.client;
import java.util.Date;
import org.hibernate.Session;

import com.infotech.entities.Employee;
import com.infotech.util.HibernateUtil;

public class SavingEntityClientTest {

	public static void main(String[] args) {
		Session session = null;
		try {
			session = HibernateUtil.getSessionFactory().openSession();
			createEmployee(session);
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			if(session != null){
				session.close();
			}
		}
	  }

	private static void createEmployee(Session session) {
		session.beginTransaction();
		Integer id =(Integer)session.save(getEmployee());
		System.out.println("Employee is created  with Id::"+id);
		session.getTransaction().commit();
	}
	
	private static Employee getEmployee(){
		Employee employee= new Employee();
		employee.setEmployeeName("Martin Bingel");
		employee.setEmail("martin.cs2017@gmail.com");
		employee.setSalary(50000.00);
		employee.setDoj(new Date());
		return employee;
	}
}

package com.infotech.client;

import java.util.Date;

import org.hibernate.Session;

import com.infotech.entities.Employee;

import com.infotech.util.HibernateUtil;

public class SavingEntityClientTest {

public static void main(String[] args) {

Session session = null;

try {

session = HibernateUtil.getSessionFactory().openSession();

createEmployee(session);

} catch (Exception e) {

e.printStackTrace();

}finally {

if(session != null){

session.close();

}

private static void createEmployee(Session session) {

session.beginTransaction();

Integer id =(Integer)session.save(getEmployee());

System.out.println("Employee is created with Id::"+id);

session.getTransaction().commit();

}

private static Employee getEmployee(){

Employee employee= new Employee();

employee.setEmployeeName("Martin Bingel");

employee.setEmail("[email protected]");

employee.setSalary(50000.00);

employee.setDoj(new Date());

return employee;

}

package com.infotech.client;
import org.hibernate.Session;
import com.infotech.entities.Employee;
import com.infotech.util.HibernateUtil;

public class DirtyCheckingClientTest {

	public static void main(String[] args) {
		Session session = null;
		try {
			session = HibernateUtil.getSessionFactory().openSession();
			Employee employee = session.get(Employee.class, 1);
			if(employee != null){
				session.beginTransaction();
				employee.setSalary(40000.00);
				employee.setEmployeeName("Martin Bingel2");
				//session.update(employee);//Even though you comment this line still 
                                // hibernate triggers update query if employee salary or name different 
                                //in the database this feature is called dirty checking in hibernate

				session.getTransaction().commit();
				//employee.setEmployeeName("Martin Bingel2");
			}else{
				System.out.println("Employeedoesn't exist with provided Id..");
			}
		} catch (Exception e) {
			e.printStackTrace();
		}finally {
			if(session != null){
				session.close();
			}
		}
	  }
}

package com.infotech.client;

import org.hibernate.Session;

import com.infotech.entities.Employee;

import com.infotech.util.HibernateUtil;

public class DirtyCheckingClientTest {

public static void main(String[] args) {

Session session = null;

try {

session = HibernateUtil.getSessionFactory().openSession();

Employee employee = session.get(Employee.class, 1);

if(employee != null){

session.beginTransaction();

employee.setSalary(40000.00);

employee.setEmployeeName("Martin Bingel2");

//session.update(employee);//Even though you comment this line still

// hibernate triggers update query if employee salary or name different

//in the database this feature is called dirty checking in hibernate

session.getTransaction().commit();

//employee.setEmployeeName("Martin Bingel2");

}else{

System.out.println("Employeedoesn't exist with provided Id..");

}

} catch (Exception e) {

e.printStackTrace();

}finally {

if(session != null){

session.close();

}

Project Structure

Step 1 – Create a maven project

Step 2 – Add jar dependencies to pom.xml

Step 3 – Create Entity class in hibernate

Step 4 – Create a Hibernate configuration file

Step 5 – Hibernate utility class which is responsible to provide SessionFactory

Step 5 – Create two client classes

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