Eclipselink ignores entity classes with lambda expressions

Question

I am building a java SE 8 (oracle 1.8.0-b129) application with EclipseLink (2.5.1, also tried 2.5.2-M1), and have an Entity class that is simply being ignored by EclipeLink, despite being correctly annotated and referenced in the persistence.xml file. The logs show no mention of the class, no schema gets generated for it, etc. Using the entity gives the 'The abstract schema type is unknown' error.

I think I have finally tracked down the cause, and thought I would share. Apparently, EclipseLink does not like classes with lambda expressions. Here is a simple class that reproduces the problem:

@Entity
public class LambdaEntity {

    @Id
    private Integer id;

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

The lambda expression does not even have to use a persistent property, its simple existence in the class is enough. Does anyone know what could cause this? I'm guessing that EclipeLink chokes on the generated bytecode, but I find it strange that it silently ignores the class.

If you try to use this Entity in an association with other, EclipseLink will give an error saying that the entity is not defined at the persistence.xml file. Part of the stacktrace:

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

Answer 1

As suggested by Michael Jess (thank you :)), here is a link to the bug report for this problem. Unfortunately I have not found the time to test the work that has been done there yet, but it looks promising. This problem should not be around much longer, it appears.