[Hibernate ORM](https://hibernate.org/orm/) is an Object/Relational Mapping (ORM) framework for Java applications. Hibernate ORM is concerned with data persistence of relational databases, and enables developers to write applications whose data outlives the application lifetime.
YugabyteDB YSQL API has full compatibility with Hibernate ORM for Data persistence in Java applications. This page provides details for getting started with Hibernate ORM for connecting to YugabyteDB.
## CRUD operations
Learn how to establish a connection to YugabyteDB database and begin basic CRUD operations using the steps in the [Java ORM example application](../../orms/java/ysql-hibernate/) page.
The following sections demonstrate how to perform common tasks required for Java application development using the Hibernate ORM.
### Step 1: Add the Hibernate ORM dependency
If you're using [Maven](https://maven.apache.org/guides/development/guide-building-maven.html), add the following to your project's `pom.xml` file.
```xml
org.hibernate
hibernate-core
5.4.19.Final
org.hibernate
hibernate-annotations
3.5.6-Final
```
If you're using [Gradle](https://docs.gradle.org/current/samples/sample_building_java_applications.html), add the following dependencies to your `build.gradle` file:
```java
implementation 'org.hibernate:hibernate-core:5.4.19.Final'
implementation 'org.hibernate:hibernate-annotations:3.5.6-Final'
```
Note: Hibernate ORM can be used with the [YugabyteDB JDBC driver](../yugabyte-jdbc) and the [PostgreSQL JDBC Driver](../postgres-jdbc).
### Step 2: Implementing ORM mapping for YugabyteDB
Create a file called `Employee.java` in the base package directory of your project and add the following code for a class that includes the following fields, setters, and getters.
```java
@Entity
@Table(name = "employee")
public class Employee {
@Id
Integer id;
String name;
Integer age;
String language;
// Setters and Getters
}
```
### Step 3: Create a DAO object for Employee object
Create a Data Access Object (DAO) `EmployeeDAO.java` in the base package directory. The DAO is used for implementing the basic CRUD operations for the domain object `Employee.java`. Copy the following sample code into your project.
```java
import org.hibernate.Session;
public class EmployeeDAO {
Session hibernateSession;
public EmployeeDAO (Session session) {
hibernateSession = session;
}
public void save(final Employee employeeEntity) {
Transaction transaction = session.beginTransaction();
try {
session.save(entity);
transaction.commit();
} catch(RuntimeException rte) {
transaction.rollback();
}
session.close();
}
public Optional findById(final Integer id) {
return Optional.ofNullable(session.get(Emplyee.class, id));
}
}
```
### Step 4: Configure Hibernate properties
Add the hibernate configurations file `hibernate.cfg.xml` to the resources directory, and copy the following contents into the file.
```xml
org.hibernate.dialect.PostgreSQLDialect
com.yugabytedb.Driver
jdbc:yugabytedb://localhost:5433/yugabyte
yugabyte
update
true
true
generate
8
thread
true
```
The Hibernate configuration file provides the generic set of properties that are required for configuring the Hibernate ORM for YugabyteDB.
| Hibernate Parameter | Description | Default |
| :---------- | :---------- | :------ |
| hibernate.dialect | Dialect to use to generate SQL optimized for a particular database | org.hibernate.dialect.PostgreSQLDialect
| hibernate.connection.driver_class | JDBC Driver name | com.yugabytedb.Driver
| hibernate.connection.url | JDBC Connection URL | jdbc:yugabytedb://localhost:5433/yugabyte
| hibernate.connection.username | Username | yugabyte
| hibernate.connection.password | Password | yugabyte
| hibernate.hbm2ddl.auto | Behaviour for automatic schema generation | none
Hibernate provides an [exhaustive list of properties](https://docs.jboss.org/hibernate/orm/5.6/userguide/html_single/Hibernate_User_Guide.html#configurations-general) to configure the different features supported by the ORM. Additional details can be obtained by referring to the [Hibernate documentation](https://hibernate.org/orm/documentation/5.6/).
### Step 5: Adding the Object relational mapping
Along with properties for configuring the Hibernate ORM, `hibernate.cfg.xml` is also used for specifying the Domain objects mapping using `` tags.
Add a mapping for `Employee` object in `hibernate.cfg.xml`
```xml
...
```
### Step 6: Query the YugabyteDB Cluster using Hibernate ORM
Create a new Java class called `QuickStartOrmApp.java` in the base package directory of your project. Copy the following sample code to query the table contents from the Java client using Hibernate ORM. Ensure you replace the parameters in the connection string `yburl` with the cluster credentials and SSL certificate, if required.
```java
import com.zaxxer.hikari.HikariConfig;
import com.zaxxer.hikari.HikariDataSource;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.Properties;
import java.util.Scanner;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
public class QuickStartOrmApp {
public static void main(String[] args) throws ClassNotFoundException, SQLException {
SessionFactory sessionFactory = HibernateUtil.getSessionFactory();
Session session = sessionFactory.openSession();
try {
System.out.println("Connected to the YugabyteDB Cluster successfully.");
EmplyeeDAO employeeDAO = new EmployeeDAO(session);
// Save an employee
employeeDAO.save(new Employee());
// Find the emplyee
Employee employee = employeeDAO.findByID(1);
System.out.println("Query Returned:" + employee.toString());
}
} catch (SQLException e) {
System.err.println(e.getMessage());
}
}
}
```
When you run the Project, QuickStartApp.java should output something like the following:
```text
Connected to the YugabyteDB Cluster successfully.
Created table employee
Inserted data: INSERT INTO employee (id, name, age, language) VALUES (1, 'John', 35, 'Java');
Query returned: name=John, age=35, language: Java
```
## Learn more
- Build Java applications using [Ebean ORM](../ebean/)
- [YugabyteDB smart drivers for YSQL](../../smart-drivers/)