Yes, the Internal state of SessionFactory is immutable, so it’s thread-safe. Multiple threads can access it simultaneously to get Session instances.

SessionFactory is the factory class used to get the Session objects. SessionFactory is responsible to read the hibernate configuration parameters and connect to the database and provide Session objects. Usually, an application has a single SessionFactory instance and threads servicing client requests obtain Session instances from this factory.

A SessionFactory is very expensive to create, so, for any given database, the application should have only one associated SessionFactory. The SessionFactory maintains services that Hibernate uses across all Session(s) such as second-level caches, connection pools, transaction system integrations, etc.

The internal state of a SessionFactory is immutable. Once it is created this internal state is set. This internal state includes all of the metadata about Object/Relational Mapping.

Below hibernate configuration file shows how to configure SessionFactory using hibernate.cfg.xml file:

<!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>
        <!-- JDBC Database connection settings -->
        <property name="connection.driver_class">com.mysql.cj.jdbc.Driver</property>
        <property name="connection.url">jdbc:mysql://localhost:3306/hibernate_db?useSSL=false</property>
        <property name="connection.username">root</property>
        <property name="connection.password">root</property>
        <!-- JDBC connection pool settings ... using built-in test pool -->
        <property name="connection.pool_size">1</property>
        <!-- Select our SQL dialect -->
        <property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>
        <!-- Echo the SQL to stdout -->
        <property name="show_sql">true</property>
        <!-- Set the current session context -->
        <property name="current_session_context_class">thread</property>
        <!-- Drop and re-create the database schema on startup -->
        <property name="hbm2ddl.auto">create-drop</property>
        <!-- dbcp connection pool configuration -->
        <property name="hibernate.dbcp.initialSize">5</property>
        <property name="hibernate.dbcp.maxTotal">20</property>
        <property name="hibernate.dbcp.maxIdle">10</property>
        <property name="hibernate.dbcp.minIdle">5</property>
        <property name="hibernate.dbcp.maxWaitMillis">-1</property>
        <mapping class="net.javaguides.hibernate.entity.Student" />
    </session-factory>
</hibernate-configuration>