I am using Spring, JPA, and Hibernate. This is a toy example that I am using to debug a larger JPA-related issue. However, this simple example of trying to persist a very basic entity, \[code\]HelloBean\[/code\], seems to create detached objects. As far as I am aware, calling \[code\]persist\[/code\] on the \[code\]EntityManager\[/code\] object should set the entity to be managed by the persistence context. However, it does not, and \[code\]merge\[/code\] does not work for this either. The output is as follows::\[code\]Starting...Service found in context as: net.solasistim.hello.HelloService@3b7a687bHibernate: insert into HelloBean (message) values (?)Is bean attached? = falseHibernate: select hellobean0_.id as id1_0_0_, hellobean0_.message as message2_0_0_ from HelloBean hellobean0_ where hellobean0_.id=?Is bean attached? = false\[/code\]Imports omitted for brevity.\[code\]Hello.java\[/code\]::\[code\]public class Hello { public static void main(String[] args) throws Exception { ApplicationContext context = new ClassPathXmlApplicationContext("beans.xml"); System.out.println("Starting..."); HelloService svc = (HelloService) context.getBean("helloService"); System.out.println("Service found in context as: " + svc); HelloBean bean1 = new HelloBean(); bean1.setMessage("This is bean 1."); HelloBean bean2 = new HelloBean(); bean2.setMessage("This is bean 2."); svc.persist(bean2); System.out.println("Is bean attached? = " + svc.isAttached(bean2)); HelloBean newBean = svc.merge(bean2); System.out.println("Is bean attached? = " + svc.isAttached(newBean)); }}\[/code\]\[code\]HelloService.java\[/code\]::\[code\]@Service@Transactionalpublic class HelloService { @PersistenceContext private EntityManager em; public void persist(HelloBean entity) { em.persist(entity); } public HelloBean merge(HelloBean entity) { return em.merge(entity); } public void delete(HelloBean entity) { em.remove(entity); } public boolean isAttached(HelloBean entity) { return em.contains(entity); }}\[/code\]\[code\]HelloBean.java\[/code\]::\[code\]@Entitypublic class HelloBean { @Id @GeneratedValue private long id; private String message; public void setMessage(String message) { this.message = message; } public String getMessage() { return this.message; }}\[/code\]\[code\]pom.xml\[/code\]::\[code\]<project> <modelVersion>4.0.0</modelVersion> <groupId>net.solasistim.hello</groupId> <artifactId>hello</artifactId> <version>1</version> <packaging>jar</packaging> <properties> <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding> </properties> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-context</artifactId> <version>3.2.2.RELEASE</version> </dependency> <dependency> <groupId>org.springframework</groupId> <artifactId>spring-orm</artifactId> <version>3.2.2.RELEASE</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-core</artifactId> <version>4.2.0.Final</version> </dependency> <dependency> <groupId>org.hibernate</groupId> <artifactId>hibernate-entitymanager</artifactId> <version>4.2.0.Final</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.24</version> </dependency> </dependencies></project>\[/code\]\[code\]beans.xml\[/code\]::\[code\]<?xml version="1.0" encoding="UTF-8"?><beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd"> <context:component-scan base-package="net.solasistim.hello"/> <context:annotation-config /> <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean"> <property name="persistenceUnitName" value="http://stackoverflow.com/questions/15784679/my-persistence-unit"/> </bean> <!-- These two are needed for @Transactional annotations to be processed. Nothing will be committed without them. --> <tx:annotation-driven/> <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager"> <property name="entityManagerFactory" ref="entityManagerFactory" /> </bean></beans>\[/code\]\[code\]persistence.xml\[/code\]::\[code\]<?xml version="1.0"?><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="my-persistence-unit"> <provider>org.hibernate.ejb.HibernatePersistence</provider> <properties> <property name="hibernate.dialect" value="http://stackoverflow.com/questions/15784679/org.hibernate.dialect.MySQLDialect" /> <property name="hibernate.connection.driver_class" value="http://stackoverflow.com/questions/15784679/com.mysql.jdbc.Driver" /> <property name="hibernate.connection.url" value="http://stackoverflow.com/questions/15784679/jdbc:mysql://localhost:3306/jpa_test" /> <property name="hibernate.connection.username" value="http://stackoverflow.com/questions/15784679/root" /> <property name="hibernate.connection.password" value="" /> <property name="hibernate.show_sql" value="http://stackoverflow.com/questions/15784679/true" /> <property name="hibernate.hbm2ddl.auto" value="http://stackoverflow.com/questions/15784679/create" /> </properties> </persistence-unit></persistence>\[/code\]
Why do my entities remain detached after persisting them in JPA?
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