HHH-11116 - Improve the JPA bootstrapping section in the User Guide
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Vlad Mihalcea
parent
9498b52566
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2b30cabf2f
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@ -1,6 +1,7 @@
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[[bootstrap]]
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== Bootstrap
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:sourcedir: ../../../../../test/java/org/hibernate/userguide/bootstrap
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:extrasdir: extras
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The term bootstrapping refers to initializing and starting a software component.
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In Hibernate, we are specifically talking about the process of building a fully functional `SessionFactory` instance or `EntityManagerFactory` instance, for JPA.
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@ -18,6 +19,69 @@ Instead, we focus here on the API calls needed to perform the bootstrapping.
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During the bootstrap process, you might want to customize Hibernate behavior so make sure you check the <<appendices/Configurations.adoc#configurations,Configurations>> section as well.
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====
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[[bootstrap-jpa]]
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=== JPA Bootstrapping
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Bootstrapping Hibernate as a JPA provider can be done in a JPA-spec compliant manner or using a proprietary bootstrapping approach.
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The standardized approach has some limitations in certain environments, but aside from those, it is *highly* recommended that you use JPA-standardized bootstrapping.
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[[bootstrap-jpa-compliant]]
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==== JPA-compliant bootstrapping
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In JPA, we are ultimately interested in bootstrapping a `javax.persistence.EntityManagerFactory` instance.
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The JPA specification defines two primary standardized bootstrap approaches depending on how the application intends to access the `javax.persistence.EntityManager` instances from an `EntityManagerFactory`.
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It uses the terms _EE_ and _SE_ for these two approaches, but those terms are very misleading in this context.
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What the JPA spec calls EE bootstrapping implies the existence of a container (EE, OSGi, etc), who'll manage and inject the persistence context on behalf of the application.
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What it calls SE bootstrapping is everything else. We will use the terms container-bootstrapping and application-bootstrapping in this guide.
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[NOTE]
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====
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If you would like additional details on accessing and using `EntityManager` instances, sections 7.6 and 7.7 of the JPA 2.1 specification cover container-managed and application-managed `EntityManagers`, respectively.
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====
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For compliant container-bootstrapping, the container will build an `EntityManagerFactory` for each persistent-unit defined in the `META-INF/persistence.xml` configuration file
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and make that available to the application for injection via the `javax.persistence.PersistenceUnit` annotation or via JNDI lookup.
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[[bootstrap-jpa-compliant-PersistenceUnit-example]]
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.Injecting a EntityManagerFactory
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====
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[source, JAVA, indent=0]
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----
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include::{sourcedir}/BootstrapTest.java[tags=bootstrap-jpa-compliant-PersistenceUnit-example]
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----
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====
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The `META-INF/persistence.xml` file looks as follows:
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[[bootstrap-jpa-compliant-persistence-xml-example]]
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.META-INF/persistence.xml configuration file
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====
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[source, JAVA, indent=0]
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----
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include::{extrasdir}/persistence.xml[]
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----
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====
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For compliant application-bootstrapping, rather than the container building the `EntityManagerFactory` for the application, the application builds the `EntityManagerFactory` itself using the `javax.persistence.Persistence` bootstrap class.
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The application creates an `EntityManagerFactory` by calling the `createEntityManagerFactory` method:
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[[bootstrap-jpa-compliant-EntityManagerFactory-example]]
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.Application bootstrapped EntityManagerFactory
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====
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[source, JAVA, indent=0]
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----
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include::{sourcedir}/BootstrapTest.java[tags=bootstrap-jpa-compliant-EntityManagerFactory-example]
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----
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====
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[NOTE]
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====
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If you don't want to provide a `persistence.xml` configuration file, JPA allows you to provide all the configuration options in a
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http://docs.oracle.com/javaee/7/api/javax/persistence/spi/PersistenceUnitInfo.html[PersistenceUnitInfo] implementation and call
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https://docs.jboss.org/hibernate/orm/{majorMinorVersion}/javadocs/org/hibernate/jpa/HibernatePersistenceProvider.html#createContainerEntityManagerFactory-javax.persistence.spi.PersistenceUnitInfo-java.util.Map-[HibernatePersistenceProvider.html#createContainerEntityManagerFactory].
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====
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[[bootstrap-native]]
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=== Native Bootstrapping
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@ -176,68 +240,4 @@ The bootstrapping API is quite flexible, but in most cases it makes the most sen
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----
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include::{sourcedir}/BootstrapTest.java[tags=bootstrap-native-SessionFactoryBuilder-example]
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----
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====
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[[bootstrap-jpa]]
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=== JPA Bootstrapping
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Bootstrapping Hibernate as a JPA provider can be done in a JPA-spec compliant manner or using a proprietary bootstrapping approach.
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The standardized approach has some limitations in certain environments, but aside from those, it is *highly* recommended that you use JPA-standardized bootstrapping.
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[[bootstrap-jpa-compliant]]
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==== JPA-compliant bootstrapping
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In JPA, we are ultimately interested in bootstrapping a `javax.persistence.EntityManagerFactory` instance.
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The JPA specification defines 2 primary standardized bootstrap approaches depending on how the application intends to access the `javax.persistence.EntityManager` instances from an `EntityManagerFactory`.
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It uses the terms _EE_ and _SE_ for these two approaches, but those terms are very misleading in this context.
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What the JPA spec calls EE bootstrapping implies the existence of a container (EE, OSGi, etc), who'll manage and inject the persistence context on behalf of the application.
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What it calls SE bootstrapping is everything else. We will use the terms container-bootstrapping and application-bootstrapping in this guide.
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If you would like additional details on accessing and using `EntityManager` instances, sections 7.6 and 7.7 of the JPA 2.1 specification cover container-managed and application-managed `EntityManagers`, respectively.
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For compliant container-bootstrapping, the container will build an `EntityManagerFactory` for each persistent-unit defined in the `META-INF/persistence.xml` configuration file
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and make that available to the application for injection via the `javax.persistence.PersistenceUnit` annotation or via JNDI lookup.
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[[bootstrap-jpa-compliant-PersistenceUnit-example]]
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.Injecting a EntityManagerFactory
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====
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[source, JAVA, indent=0]
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----
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include::{sourcedir}/BootstrapTest.java[tags=bootstrap-jpa-compliant-PersistenceUnit-example]
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----
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====
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For compliant application-bootstrapping, rather than the container building the `EntityManagerFactory` for the application, the application builds the `EntityManagerFactory` itself using the `javax.persistence.Persistence` bootstrap class.
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The application creates an `EntityManagerFactory` by calling the `createEntityManagerFactory` method:
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[[bootstrap-jpa-compliant-EntityManagerFactory-example]]
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.Application bootstrapped EntityManagerFactory
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====
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[source, JAVA, indent=0]
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----
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include::{sourcedir}/BootstrapTest.java[tags=bootstrap-jpa-compliant-EntityManagerFactory-example]
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----
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====
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[[bootstrap-jpa-hibernate]]
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==== Proprietary JPA bootstrapping
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Hibernate defines a proprietary https://docs.jboss.org/hibernate/orm/{majorMinorVersion}/javadocs/org/hibernate/jpa/boot/internal/EntityManagerFactoryBuilderImpl.html[`EntityManagerFactoryBuilderImpl`]
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utility, which allows bootstrapping the JPA environment without even in the absence of the `persistence.xml` configuration file.
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To substitute the `persistence.xml` file, Hibernate offers the `PersistenceUnitInfoDescriptor` utility, which can take configuration that's available in the standard XML configuration file.
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[[bootstrap-native-EntityManagerFactory-example]]
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.Proprietary bootstrapped `EntityManagerFactory`
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====
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[source, JAVA, indent=0]
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----
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include::{sourcedir}/BootstrapTest.java[tags=bootstrap-native-PersistenceUnitInfoImpl-example]
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----
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[source, JAVA, indent=0]
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----
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include::{sourcedir}/BootstrapTest.java[tags=bootstrap-native-EntityManagerFactory-example]
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----
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====
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The `integrationSettings` allows the application developer to customize the bootstrapping process by specifying different `hibernate.integrator_provider` or `hibernate.strategy_registration_provider` integration providers.
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====
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@ -0,0 +1,38 @@
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<persistence xmlns="http://xmlns.jcp.org/xml/ns/persistence"
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xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
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xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/persistence
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http://xmlns.jcp.org/xml/ns/persistence/persistence_2_1.xsd"
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version="2.1">
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<persistence-unit name="CRM">
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<description>
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Persistence unit for Hibernate User Guide
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</description>
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<provider>org.hibernate.jpa.HibernatePersistenceProvider</provider>
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<class>org.hibernate.documentation.userguide.Document</class>
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<properties>
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<property name="javax.persistence.jdbc.driver"
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value="org.h2.Driver" />
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<property name="javax.persistence.jdbc.url"
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value="jdbc:h2:mem:db1;DB_CLOSE_DELAY=-1;MVCC=TRUE" />
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<property name="javax.persistence.jdbc.user"
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value="sa" />
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<property name="javax.persistence.jdbc.password"
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value="" />
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<property name="hibernate.show_sql"
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value="true" />
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<property name="hibernate.hbm2ddl.auto"
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value="update" />
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</properties>
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</persistence-unit>
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</persistence>
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