This package defines APIs for configuring Hibernate.

• org.hibernate.cfg.AvailableSettings enumerates all the configuration properties recognized by Hibernate.
• org.hibernate.cfg.Configuration provides a simplified API for bootstrapping Hibernate, as an alternative to the more extensive facilities defined under org.hibernate.boot.

Note that all the real meat behind these APIs is defined in the package org.hibernate.boot.

Configuration properties may be specified:

• in Java code that configures Hibernate,
• in a JPA configuration file named persistence.xml,
• in a native configuration file named hibernate.cfg.xml,
• in a file named hibernate.properties, or
• using some container-specific configuration facility, for example, Quarkus configuration properties.

We now present a couple of example configuration files.

Example JPA configuration file

The following JPA configuration may be specified in a file named persistence.xml:

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
             xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
             xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd"
             version="2.0">

    <persistence-unit name="postgresql-example" transaction-type="RESOURCE_LOCAL">

        <class>org.hibernate.orm.example.Author</class>
        <class>org.hibernate.orm.example.Book</class>

        <properties>

            <!-- PostgreSQL -->
            <property name="javax.persistence.jdbc.url"
                      value="jdbc:postgresql://localhost/library"/>

            <!-- Credentials -->
            <property name="javax.persistence.jdbc.user"
                      value="hibernate"/>
            <property name="javax.persistence.jdbc.password"
                      value="hibernate"/>

            <!-- Agroal connection pool config -->
            <property name="hibernate.agroal.maxSize"
                      value="10"/>
            <property name="hibernate.agroal.acquisitionTimeout"
                      value="PT1s"/>
            <property name="hibernate.agroal.reapTimeout"
                      value="PT10s"/>

            <!-- Automatic schema export -->
            <property name="javax.persistence.schema-generation.database.action"
                      value="drop-and-create"/>

            <!-- SQL statement logging -->
            <property name="hibernate.show_sql" value="true"/>
            <property name="hibernate.format_sql" value="true"/>
            <property name="hibernate.highlight_sql" value="true"/>

        </properties>
    </persistence-unit>

</persistence>

The JPA configuration file is necessary when bootstrapping Hibernate via jakarta.persistence.Persistence#createEntityManagerFactory(java.lang.String).

Example native configuration file

The following configuration may be specified in a file named hibernate.cfg.xml:

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

<hibernate-configuration>
    <session-factory>
        <!-- PostgreSQL -->
        <property name="javax.persistence.jdbc.url">jdbc:postgresql://localhost/library</property>

        <!-- Credentials -->
        <property name="hibernate.connection.username">hibernate</property>
        <property name="hibernate.connection.password">hibernate</property>

        <!-- Agroal connection pool config -->
        <property name="hibernate.agroal.maxSize">10</property>
        <property name="hibernate.agroal.acquisitionTimeout">PT1s</property>
        <property name="hibernate.agroal.reapTimeout">PT10s</property>

        <!-- Automatic schema export -->
        <property name="hibernate.hbm2ddl.auto">create</property>

        <!-- SQL statement logging -->
        <property name="hibernate.show_sql">true</property>
        <property name="hibernate.format_sql">true</property>
        <property name="hibernate.highlight_sql">true</property>

        <!-- Maximum JDBC batch size -->
        <property name="hibernate.jdbc.batch_size">10</property>

        <!-- Entity classes -->
        <mapping class="org.hibernate.orm.example.Author"/>
        <mapping class="org.hibernate.orm.example.Book"/>

    </session-factory>
</hibernate-configuration>

The native configuration file is used when configuring Hibernate via org.hibernate.cfg.Configuration#configure() or org.hibernate.boot.registry.StandardServiceRegistryBuilder#configure().