No [EntityType] was found for the key class [...] in the Metamodel

Question

Entity:

@Entity
@Table(name="user_account")
public class UserAccount implements Serializable{
    private static final long serialVersionUID = -2606506548742732094L;

    @Id
    @GeneratedValue(strategy=GenerationType.TABLE)
    private Integer id;

persistence.xml

<persistence-unit name="Maze" transaction-type="RESOURCE_LOCAL">

    <exclude-unlisted-classes>false</exclude-unlisted-classes>
    <properties>
        <property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver"/>
        <property name="javax.persistence.jdbc.url" value="jdbc:mysql://localhost:3306/mazedb"/>
        <property name="javax.persistence.jdbc.user" value="root"/>
        <property name="javax.persistence.jdbc.password" value="root"/>
    </properties>

</persistence-unit>

The error

WARNING: #{accountController.performLogin}: java.lang.IllegalArgumentException: No [EntityType] was found for the key class [com.maze.model.UserAccount] in the Metamodel - please verify that the [Entity] class was referenced in persistence.xml using a specific <class>com.maze.model.UserAccount</class> property or a global <exclude-unlisted-classes>false</exclude-unlisted-classes> element.
javax.faces.FacesException: #{accountController.performLogin}: java.lang.IllegalArgumentException: No [EntityType] was found for the key class [com.maze.model.UserAccount] in the Metamodel - please verify that the [Entity] class was referenced in persistence.xml using a specific <class>com.maze.model.UserAccount</class> property or a global <exclude-unlisted-classes>false</exclude-unlisted-classes> element.
    at com.sun.faces.application.ActionListenerImpl.processAction(ActionListenerImpl.java:118)
    at javax.faces.component.UICommand.broadcast(UICommand.java:315)
    at javax.faces.component.UIViewRoot.broadcastEvents(UIViewRoot.java:794)
    at javax.faces.component.UIViewRoot.processApplication(UIViewRoot.java:1259)
    at com.sun.faces.lifecycle.InvokeApplicationPhase.execute(InvokeApplicationPhase.java:81)
    at com.sun.faces.lifecycle.Phase.doPhase(Phase.java:101)
    at com.sun.faces.lifecycle.LifecycleImpl.execute(LifecycleImpl.java:118)
    at javax.faces.webapp.FacesServlet.service(FacesServlet.java:593)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1539)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:281)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:175)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:655)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:595)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:98)
    at com.sun.enterprise.web.PESessionLockingStandardPipeline.invoke(PESessionLockingStandardPipeline.java:91)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:162)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:330)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:231)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:174)
    at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
    at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
    at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
    at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
    at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
    at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
    at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
    at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
    at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
    at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
    at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
    at java.lang.Thread.run(Thread.java:662)

Behaviour Every time I restart the Web Container everything works just fine for a couple of minutes and than this error gets thrown. What am I missing?

EDIT :

Now I use an entity on the application scope as well and the same error occurs for the Country Entity. Both User and Country are defined as classes in the persistance.xml. Furthermore the exclude-unlisted-classes is set to false.

SEVERE: Critical error during deployment: 
java.lang.ExceptionInInitializerError
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at     sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39    )
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:513)
at java.lang.Class.newInstance0(Class.java:355)
at java.lang.Class.newInstance(Class.java:308)
at com.sun.faces.mgbean.BeanBuilder.newBeanInstance(BeanBuilder.java:188)
at com.sun.faces.mgbean.BeanBuilder.build(BeanBuilder.java:102)
at com.sun.faces.mgbean.BeanManager.createAndPush(BeanManager.java:409)
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:269)
at com.sun.faces.mgbean.BeanManager.create(BeanManager.java:256)
at com.sun.faces.config.ConfigureListener.contextInitialized(ConfigureListener.java:255)
at org.apache.catalina.core.StandardContext.contextListenerStart(StandardContext.java:4750)
at com.sun.enterprise.web.WebModule.contextListenerStart(WebModule.java:550)
at org.apache.catalina.core.StandardContext.start(StandardContext.java:5366)
at com.sun.enterprise.web.WebModule.start(WebModule.java:498)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:917)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:901)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:733)
at com.sun.enterprise.web.WebContainer.loadWebModule(WebContainer.java:2000)
at com.sun.enterprise.web.WebContainer.loadWebModule(WebContainer.java:1651)
at com.sun.enterprise.web.WebApplication.start(WebApplication.java:109)
at org.glassfish.internal.data.EngineRef.start(EngineRef.java:130)
at org.glassfish.internal.data.ModuleInfo.start(ModuleInfo.java:269)
at org.glassfish.internal.data.ApplicationInfo.start(ApplicationInfo.java:294)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:462)
at com.sun.enterprise.v3.server.ApplicationLifecycle.deploy(ApplicationLifecycle.java:240)
at org.glassfish.deployment.admin.DeployCommand.execute(DeployCommand.java:382)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$1.execute(CommandRunnerImpl.java:355)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:370)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.doCommand(CommandRunnerImpl.java:1064)
at com.sun.enterprise.v3.admin.CommandRunnerImpl.access$1200(CommandRunnerImpl.java:96)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1244)
at com.sun.enterprise.v3.admin.CommandRunnerImpl$ExecutionContext.execute(CommandRunnerImpl.java:1232)
at com.sun.enterprise.v3.admin.AdminAdapter.doCommand(AdminAdapter.java:459)
at com.sun.enterprise.v3.admin.AdminAdapter.service(AdminAdapter.java:209)
at com.sun.grizzly.tcp.http11.GrizzlyAdapter.service(GrizzlyAdapter.java:168)
at com.sun.enterprise.v3.server.HK2Dispatcher.dispath(HK2Dispatcher.java:117)
at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:238)
at com.sun.grizzly.http.ProcessorTask.invokeAdapter(ProcessorTask.java:828)
at com.sun.grizzly.http.ProcessorTask.doProcess(ProcessorTask.java:725)
at com.sun.grizzly.http.ProcessorTask.process(ProcessorTask.java:1019)
at com.sun.grizzly.http.DefaultProtocolFilter.execute(DefaultProtocolFilter.java:225)
at com.sun.grizzly.DefaultProtocolChain.executeProtocolFilter(DefaultProtocolChain.java:137)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:104)
at com.sun.grizzly.DefaultProtocolChain.execute(DefaultProtocolChain.java:90)
at com.sun.grizzly.http.HttpProtocolChain.execute(HttpProtocolChain.java:79)
at com.sun.grizzly.ProtocolChainContextTask.doCall(ProtocolChainContextTask.java:54)
at com.sun.grizzly.SelectionKeyContextTask.call(SelectionKeyContextTask.java:59)
at com.sun.grizzly.ContextTask.run(ContextTask.java:71)
at com.sun.grizzly.util.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:532)
at com.sun.grizzly.util.AbstractThreadPool$Worker.run(AbstractThreadPool.java:513)
at java.lang.Thread.run(Thread.java:662)
Caused by: java.lang.IllegalArgumentException: No [EntityType] was found for the key class [com.maze.model.Country] in the Metamodel - please verify that the [Entity] class was referenced in persistence.xml using a specific <class>com.maze.model.Country</class> property or a global <exclude-unlisted-classes>false</exclude-unlisted-classes> element.
at org.eclipse.persistence.internal.jpa.metamodel.MetamodelImpl.entityEmbeddableManagedTypeNotFound(MetamodelImpl.java:174)
at org.eclipse.persistence.internal.jpa.metamodel.MetamodelImpl.entity(MetamodelImpl.java:194)
at org.eclipse.persistence.internal.jpa.querydef.AbstractQueryImpl.from(AbstractQueryImpl.java:97)
at com.maze.service.CountryService.readList(CountryService.java:74)
at com.maze.util.MazeConstants.<clinit>(MazeConstants.java:26)

The Country entity:

@Entity
@Table(name = "country")
public class Country implements Serializable{

private static final long serialVersionUID = 4086034429815316972L;

@Id
private Integer id;
private String name;
private String continent;
private Integer population;
private Float surface;

@OneToMany(mappedBy = "country")
private List<User> userList;

Now that this entity is used on application scope and the Entity throws this error the Glassfish fails to start completely.

SECOND EDIT : Based on the current behavior it seems that the web container starts and works fine until the first hot deployment.

Answer 1

The problem is your hot deploying of your application. The old persistence unit is sticking around in the server because you never closed the old factory, so after the hot deploy the factory still has the old classes, so you get the class cast error.

You need to clear out the old persistence unit. Closing the EntityManagerFactory should do this, such as in a Servlet destroy callback.

If you use a managed persistence unit, then everything should get cleaned up automatically. The issue is in how you are managing your persistence unit.

I think there is also a bug for this logged on EclipseLink, you might want to vote for that bug.

Answer 2

I once encountered a similar problem. The exception was sometimes thrown, sometimes not. After a painful amount of time debugging I found out it was caused by a second persistence.xml file (containing a persistence unit with an identical name) included in another jar on the classpath.