what is session factory in hibernate code example

Example: hibernate session factory

protected void setUp() throws Exception {
	// A SessionFactory is set up once for an application!
	final StandardServiceRegistry registry = new StandardServiceRegistryBuilder()
			.configure() // configures settings from hibernate.cfg.xml
			.build();
	try {
		sessionFactory = new MetadataSources( registry ).buildMetadata().buildSessionFactory();
	}
	catch (Exception e) {
		// The registry would be destroyed by the SessionFactory, but we had trouble building the SessionFactory
		// so destroy it manually.
		StandardServiceRegistryBuilder.destroy( registry );
	}
}