Unable to define/override @Version on a subclass

Question

Technology: GWT + JPA + Hibernate.

Classes DependentVariableRefinementDao & IndependentVariableRefinementDao inherit from VariableRefinementDao.

Classes DependentVariableRefinement & IndependentVariableRefinement inherit from VariableRefinement.

Entity classes annotated with @Configurable, @Entity, @Table(name=<table_name>). VariableRefinement annotated also with @Inheritance(strategy=InheritanceType.TABLE_PER_CLASS) VariableRefinement has the attribute Integer version, annotated with @Version, @Column(name="version").

When I deploy as a web app (development mode in GWT) I get the following:

[ERROR] 500 - POST /roo/ContextService (127.0.0.1) 57 bytes
Request headers
Host: 127.0.0.1:8888
Connection: keep-alive
Content-Length: 126
X-GWT-Module-Base: http://127.0.0.1:8888/roo/
X-GWT-Permutation: HostedMode
Origin: http://127.0.0.1:8888
User-Agent: Mozilla/5.0 (Windows NT 6.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/34.0.1847.116 Safari/537.36
Content-Type: text/x-gwt-rpc; charset=UTF-8
Accept: */*
Referer: <url:port>
Accept-Encoding: gzip,deflate,sdch
Accept-Language: it-IT,it;q=0.8,en-US;q=0.6,en;q=0.4
Response headers
Content-Type: text/plain

[WARN] Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 
'public abstract java.util.List <base_package>.client.service.ContextService.findAll() throws <base_package>.shared.exception.FindException'
threw an unexpected exception:
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource 
[META-INF/spring/applicationContext.xml]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException: 
[PersistenceUnit: persistenceUnit] Unable to build EntityManagerFactory
at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:389)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:579)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:208)
at com.google.gwt.user.server.rpc.RemoteServiceServlet.processPost(RemoteServiceServlet.java:248)
at com.google.gwt.user.server.rpc.AbstractRemoteServiceServlet.doPost(AbstractRemoteServiceServlet.java:62)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:727)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:362)
at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:729)
at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.handler.RequestLogHandler.handle(RequestLogHandler.java:49)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:324)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:505)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:843)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:647)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:211)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:380)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:395)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:488)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'entityManagerFactory' defined in class path resource 
[META-INF/spring/applicationContext.xml]: Invocation of init method failed; nested exception is javax.persistence.PersistenceException:
[PersistenceUnit: persistenceUnit] Unable to build EntityManagerFactory
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1482)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:521)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:295)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:292)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1117)
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:922)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:139)
at org.springframework.context.support.ClassPathXmlApplicationContext.<init>(ClassPathXmlApplicationContext.java:83)
at <base_package>.server.controller.AbstractController.findAll(AbstractController.java:106)
at <base_package>.server.service.ContextServiceImpl.findAll(ContextServiceImpl.java:66)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:606)
at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:561)
... 22 more
Caused by: javax.persistence.PersistenceException:
[PersistenceUnit: persistenceUnit] Unable to build EntityManagerFactory
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:924)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:899)
at org.hibernate.ejb.HibernatePersistence.createContainerEntityManagerFactory(HibernatePersistence.java:76)
at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:288)
at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:310)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1541)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1479)
... 40 more
Caused by: org.hibernate.AnnotationException: Unable to define/override @Version on a subclass: <base_package>.shared.domain.DependentVariableRefinement
at org.hibernate.cfg.AnnotationBinder.processElementAnnotations(AnnotationBinder.java:1530)
at org.hibernate.cfg.AnnotationBinder.processIdPropertiesIfNotAlready(AnnotationBinder.java:767)
at org.hibernate.cfg.AnnotationBinder.bindClass(AnnotationBinder.java:686)
at org.hibernate.cfg.Configuration$MetadataSourceQueue.processAnnotatedClassesQueue(Configuration.java:3512)
at org.hibernate.cfg.Configuration$MetadataSourceQueue.processMetadata(Configuration.java:3466)
at org.hibernate.cfg.Configuration.secondPassCompile(Configuration.java:1355)
at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1756)
at org.hibernate.ejb.EntityManagerFactoryImpl.<init>(EntityManagerFactoryImpl.java:96)
at org.hibernate.ejb.Ejb3Configuration.buildEntityManagerFactory(Ejb3Configuration.java:914)
... 46 more

Persistence.xml

<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" version="2.0" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_2_0.xsd">
<persistence-unit name="persistenceUnit" transaction-type="RESOURCE_LOCAL">
    <provider>org.hibernate.ejb.HibernatePersistence</provider>
    <properties>
        <property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect"/>
        <!-- value="create" to build a new database on each run; value="update" to modify an existing database; value="create-drop" means the same as "create" but also drops tables when Hibernate closes; value="validate" makes no changes to the database -->
        <property name="hibernate.hbm2ddl.auto" value="update"/>
        <property name="hibernate.ejb.naming_strategy" value="org.hibernate.cfg.ImprovedNamingStrategy"/>
        <property name="hibernate.connection.charSet" value="UTF-8"/>
        <!-- Uncomment the following two properties for JBoss only -->
        <!-- property name="hibernate.validator.apply_to_ddl" value="false" /-->
        <!-- property name="hibernate.validator.autoregister_listeners" value="false" /-->
    </properties>
</persistence-unit>

 applicationContext.xml
 <?xml version="1.0" encoding="UTF-8" standalone="no"?>
 <beans  <urls>>
<context:property-placeholder location="classpath*:META-INF/spring/*.properties"/>
<context:spring-configured/>
<context:component-scan base-package="<base_package>">
    <context:exclude-filter expression=".*_Roo_.*" type="regex"/>
    <context:exclude-filter expression="org.springframework.stereotype.Controller" type="annotation"/>
</context:component-scan>
<bean class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close" id="dataSource">
    <property name="driverClassName" value="${database.driverClassName}"/>
    <property name="url" value="${database.url}"/>
    <property name="username" value="${database.username}"/>
    <property name="password" value="${database.password}"/>
    <property name="testOnBorrow" value="true"/>
    <property name="testOnReturn" value="true"/>
    <property name="testWhileIdle" value="true"/>
    <property name="timeBetweenEvictionRunsMillis" value="1800000"/>
    <property name="numTestsPerEvictionRun" value="3"/>
    <property name="minEvictableIdleTimeMillis" value="1800000"/>
    <property name="validationQuery" value="SELECT 1"/>
</bean>
<bean class="org.springframework.orm.jpa.JpaTransactionManager" id="transactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory"/>
</bean>
<tx:annotation-driven mode="proxy" transaction-manager="transactionManager"/>
<bean class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean" id="entityManagerFactory">
    <property name="persistenceUnitName" value="persistenceUnit"/>
    <property name="dataSource" ref="dataSource"/>
</bean>
<bean id="DependentVariableRefinementDao" class="base_package>.server.dao.DependentVariableRefinementDao"/>
<bean id="IndependentVariableDao" class="base_package>.server.dao.IndependentVariableDao"/>
<bean id="IndependentVariableRefinementDao" class="base_package>.server.dao.IndependentVariableRefinementDao"/>
<bean id="VariableRefinementDao" class="base_package>.server.dao.VariableRefinementDao"/>

If I: 1) Copy the code from the superclass into the two subclasses 2) Remove the superclass 3) Change the applicationContext accordingly (remove one line)

everything works correctly.

Answer 1

I replaced @Inheritance(strategy=InheritanceType.TABLE_PER_CLASS) with @MappedSuperclass and it worked as expected: no table for the super class (abstract) and field replicated into the tables corresponding to the concrete subclasses.