我在netbean里面写数据库桌面程序的时候，运行项目，结果出现这样的错误，我不知道是什么原因，请大神指教：
（由于帖子长度有限，我只能贴出一部分的错误）
- XML code
run：2011-12-13 11:06:46 org.jdesktop.application.Application$1 run严重: Application class cutomerrecords.CustomerRecordsApp failed to launchjavax.persistence.PersistenceException: No Persistence provider for EntityManager named localhost:1433;databaseName=scPU: Provider named oracle.toplink.essentials.PersistenceProvider threw unexpected exception at create EntityManagerFactory: oracle.toplink.essentials.exceptions.PersistenceUnitLoadingExceptionLocal Exception Stack: Exception [TOPLINK-30005] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.PersistenceUnitLoadingExceptionException Description: An exception was thrown while searching for persistence archives with ClassLoader: sun.misc.Launcher$AppClassLoader@19821fInternal Exception: javax.persistence.PersistenceException: Exception [TOPLINK-28018] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EntityManagerSetupExceptionException Description: predeploy for PersistenceUnit [localhost:1433;databaseName=scPU] failed.Internal Exception: Exception [TOPLINK-7250] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.ValidationExceptionException Description: [class cutomerrecords.Customers] uses a non-entity [class cutomerrecords.Countries] as target entity in the relationship attribute [private cutomerrecords.Countries cutomerrecords.Customers.countryId]. at oracle.toplink.essentials.exceptions.PersistenceUnitLoadingException.exceptionSearchingForPersistenceResources(PersistenceUnitLoadingException.java:143) at oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider.createEntityManagerFactory(EntityManagerFactoryProvider.java:169) at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:110) at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:83) at cutomerrecords.CustomerRecordsView.initComponents(CustomerRecordsView.java:342) at cutomerrecords.CustomerRecordsView.<init>(CustomerRecordsView.java:39) at cutomerrecords.CustomerRecordsApp.startup(CustomerRecordsApp.java:19) at org.jdesktop.application.Application$1.run(Application.java:171) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209) at java.awt.EventQueue.dispatchEvent(EventQueue.java:597) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)Caused by: javax.persistence.PersistenceException: Exception [TOPLINK-28018] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EntityManagerSetupExceptionException Description: predeploy for PersistenceUnit [localhost:1433;databaseName=scPU] failed.Internal Exception: Exception [TOPLINK-7250] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.ValidationExceptionException Description: [class cutomerrecords.Customers] uses a non-entity [class cutomerrecords.Countries] as target entity in the relationship attribute [private cutomerrecords.Countries cutomerrecords.Customers.countryId]. at oracle.toplink.essentials.internal.ejb.cmp3.EntityManagerSetupImpl.predeploy(EntityManagerSetupImpl.java:643) at oracle.toplink.essentials.internal.ejb.cmp3.JavaSECMPInitializer.callPredeploy(JavaSECMPInitializer.java:171) at oracle.toplink.essentials.internal.ejb.cmp3.JavaSECMPInitializer.initPersistenceUnits(JavaSECMPInitializer.java:239) at oracle.toplink.essentials.internal.ejb.cmp3.JavaSECMPInitializer.initialize(JavaSECMPInitializer.java:255) at oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProvider.createEntityManagerFactory(EntityManagerFactoryProvider.java:155) ... 14 moreCaused by: Exception [TOPLINK-28018] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EntityManagerSetupExceptionException Description: predeploy for PersistenceUnit [localhost:1433;databaseName=scPU] failed.Internal Exception: Exception [TOPLINK-7250] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.ValidationExceptionException Description: [class cutomerrecords.Customers] uses a non-entity [class cutomerrecords.Countries] as target entity in the relationship attribute [private cutomerrecords.Countries cutomerrecords.Customers.countryId]. at oracle.toplink.essentials.exceptions.EntityManagerSetupException.predeployFailed(EntityManagerSetupException.java:228) ... 19 moreCaused by: Exception [TOPLINK-7250] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.ValidationExceptionException Description: [class cutomerrecords.Customers] uses a non-entity [class cutomerrecords.Countries] as target entity in the relationship attribute [private cutomerrecords.Countries cutomerrecords.Customers.countryId]. at oracle.toplink.essentials.exceptions.ValidationException.nonEntityTargetInRelationship(ValidationException.java:1140) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.MetadataValidator.throwNonEntityTargetInRelationship(MetadataValidator.java:321) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.accessors.RelationshipAccessor.getReferenceDescriptor(RelationshipAccessor.java:164) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.accessors.ObjectAccessor.processOneToOneForeignKeyRelationship(ObjectAccessor.java:128) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.accessors.ObjectAccessor.processOwningMappingKeys(ObjectAccessor.java:205) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.accessors.ManyToOneAccessor.process(ManyToOneAccessor.java:121) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.accessors.RelationshipAccessor.processRelationship(RelationshipAccessor.java:290) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.MetadataProject.processRelationshipDescriptors(MetadataProject.java:579) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.MetadataProject.process(MetadataProject.java:512) at oracle.toplink.essentials.internal.ejb.cmp3.metadata.MetadataProcessor.processAnnotations(MetadataProcessor.java:246) at oracle.toplink.essentials.ejb.cmp3.persistence.PersistenceUnitProcessor.processORMetadata(PersistenceUnitProcessor.java:370) at oracle.toplink.essentials.internal.ejb.cmp3.EntityManagerSetupImpl.predeploy(EntityManagerSetupImpl.java:607) ... 18 more The following providers:oracle.toplink.essentials.ejb.cmp3.EntityManagerFactoryProviderReturned null to createEntityManagerFactory. at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:154) at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:83) at cutomerrecords.CustomerRecordsView.initComponents(CustomerRecordsView.java:342) at cutomerrecords.CustomerRecordsView.<init>(CustomerRecordsView.java:39) at cutomerrecords.CustomerRecordsApp.startup(CustomerRecordsApp.java:19) at org.jdesktop.application.Application$1.run(Application.java:171) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209) at java.awt.EventQueue.dispatchEvent(EventQueue.java:597) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)Exception in thread "AWT-EventQueue-0" java.lang.Error: Application class cutomerrecords.CustomerRecordsApp failed to launch at org.jdesktop.application.Application$1.run(Application.java:177) at java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:209) at java.awt.EventQueue.dispatchEvent(EventQueue.java:597) at java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:269) at java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:184) at java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:174) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:169) at java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:161) at java.awt.EventDispatchThread.run(EventDispatchThread.java:122)Caused by: javax.persistence.PersistenceException: No Persistence provider for EntityManager named localhost:1433;databaseName=scPU: Provider named oracle.toplink.essentials.PersistenceProvider threw unexpected exception at create EntityManagerFactory: oracle.toplink.essentials.exceptions.PersistenceUnitLoadingExceptionLocal Exception Stack: Exception [TOPLINK-30005] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.PersistenceUnitLoadingExceptionException Description: An exception was thrown while searching for persistence archives with ClassLoader: sun.misc.Launcher$AppClassLoader@19821fInternal Exception: javax.persistence.PersistenceException: Exception [TOPLINK-28018] (Oracle TopLink Essentials - 2.0.1 (Build b09d-fcs (12/06/2007))): oracle.toplink.essentials.exceptions.EntityManagerSetupException