我正在使用EclipseLink（2.5.1，也尝试过2.5.2-M1）构建一个Java SE 8（oracle
1.8.0-b129）应用程序，并且拥有一个Entity类，尽管已正确注释和删除，但EclipeLink只是忽略了它在persistence.xml文件中引用。日志中没有提及该类，没有为它生成任何模式，等等。使用该实体将给出“抽象模式类型未知”错误。

我想我终于找到了原因，并认为我会分享。显然，EclipseLink不喜欢带有lambda表达式的类。这是一个重现该问题的简单类：

@Entity
public class LambdaEntity {

    @Id
    private Integer id;

    public void theLambda() {
        Arrays.asList(1, 2, 3).stream().filter(m -> m == 2);
    }
}

lambda表达式甚至不必使用持久性属性，它在类中的简单存在就足够了。有谁知道是什么原因造成的？我猜想EclipeLink会阻塞生成的字节码，但我感到奇怪的是它默默地忽略了该类。

如果尝试将此实体与其他实体结合使用，则EclipseLink将给出错误消息，指出该实体未在persistence.xml文件中定义。部分堆栈跟踪：

Local Exception Stack: 
Exception [EclipseLink-30005] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.PersistenceUnitLoadingException
Exception Description: An exception was thrown while searching for persistence archives with ClassLoader: sun.misc.Launcher$AppClassLoader@3b9a45b3
Internal Exception: javax.persistence.PersistenceException: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Predeployment of PersistenceUnit [hcm-test] failed.
Internal Exception: Exception [EclipseLink-7250] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.ValidationException
Exception Description: [class com.senior.hcm.domain.organization.Workstation] uses a non-entity [class com.senior.hcm.domain.auth.UserRole] as target entity in the relationship attribute [field roles].
    at org.eclipse.persistence.exceptions.PersistenceUnitLoadingException.exceptionSearchingForPersistenceResources(PersistenceUnitLoadingException.java:127)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactoryImpl(PersistenceProvider.java:107)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactory(PersistenceProvider.java:177)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:79)
    at javax.persistence.Persistence.createEntityManagerFactory(Persistence.java:54)
Caused by: javax.persistence.PersistenceException: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Predeployment of PersistenceUnit [hcm-test] failed.
Internal Exception: Exception [EclipseLink-7250] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.ValidationException
Exception Description: [class com.senior.hcm.domain.organization.Workstation] uses a non-entity [class com.senior.hcm.domain.auth.UserRole] as target entity in the relationship attribute [field roles].
    at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.createPredeployFailedPersistenceException(EntityManagerSetupImpl.java:1954)
    at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.predeploy(EntityManagerSetupImpl.java:1945)
    at org.eclipse.persistence.internal.jpa.deployment.JPAInitializer.callPredeploy(JPAInitializer.java:98)
    at org.eclipse.persistence.jpa.PersistenceProvider.createEntityManagerFactoryImpl(PersistenceProvider.java:96)
    ... 28 more
Caused by: Exception [EclipseLink-28018] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.EntityManagerSetupException
Exception Description: Predeployment of PersistenceUnit [hcm-test] failed.
Internal Exception: Exception [EclipseLink-7250] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.ValidationException
Exception Description: [class com.senior.hcm.domain.organization.Workstation] uses a non-entity [class com.senior.hcm.domain.auth.UserRole] as target entity in the relationship attribute [field roles].
    at org.eclipse.persistence.exceptions.EntityManagerSetupException.predeployFailed(EntityManagerSetupException.java:230)
    ... 32 more
Caused by: Exception [EclipseLink-7250] (Eclipse Persistence Services - 2.5.2.v20140319-9ad6abd): org.eclipse.persistence.exceptions.ValidationException
Exception Description: [class com.senior.hcm.domain.organization.Workstation] uses a non-entity [class com.senior.hcm.domain.auth.UserRole] as target entity in the relationship attribute [field roles].
    at org.eclipse.persistence.exceptions.ValidationException.nonEntityTargetInRelationship(ValidationException.java:1378)
    at org.eclipse.persistence.internal.jpa.metadata.accessors.mappings.RelationshipAccessor.getReferenceDescriptor(RelationshipAccessor.java:553)
    at org.eclipse.persistence.internal.jpa.metadata.accessors.mappings.RelationshipAccessor.getOwningMapping(RelationshipAccessor.java:469)
    at org.eclipse.persistence.internal.jpa.metadata.accessors.mappings.ManyToManyAccessor.process(ManyToManyAccessor.java:149)
    at org.eclipse.persistence.internal.jpa.metadata.MetadataProject.processNonOwningRelationshipAccessors(MetadataProject.java:1566)
    at org.eclipse.persistence.internal.jpa.metadata.MetadataProject.processStage3(MetadataProject.java:1855)
    at org.eclipse.persistence.internal.jpa.metadata.MetadataProcessor.processORMMetadata(MetadataProcessor.java:580)
    at org.eclipse.persistence.internal.jpa.deployment.PersistenceUnitProcessor.processORMetadata(PersistenceUnitProcessor.java:585)
    at org.eclipse.persistence.internal.jpa.EntityManagerSetupImpl.predeploy(EntityManagerSetupImpl.java:1869)
    ... 30 more