Neo4j Mapping Exception

Question

I am a getting a MappingException error when executing the following piece of code:

Configuration configuration = new Configuration.Builder()
                    .uri("file:///var/lib/neo4j/data/databases/graph.db")
                    .credentials("neo4j","noor")
                    .build();

            SessionFactory sessionFactory = new SessionFactory(configuration,"OntologyDescription","info.testNeo");
            Session session = sessionFactory.openSession();
            ResourceDescription classDescription = OntologyUtils.getClassDescription(classIRI,
                    dogont);
            session.save(classDescription);
            sessionFactory.close();

Full trace:

Exception in thread "main" org.neo4j.ogm.exception.core.MappingException: Field with primary id is null for entity state
    at org.neo4j.ogm.context.MappingContext.nativeId(MappingContext.java:514)
    at org.neo4j.ogm.context.EntityGraphMapper.newNodeBuilder(EntityGraphMapper.java:318)
    at org.neo4j.ogm.context.EntityGraphMapper.mapEntity(EntityGraphMapper.java:257)
    at org.neo4j.ogm.context.EntityGraphMapper.mapRelatedEntity(EntityGraphMapper.java:797)
    at org.neo4j.ogm.context.EntityGraphMapper.link(EntityGraphMapper.java:501)
    at org.neo4j.ogm.context.EntityGraphMapper.mapEntityReferences(EntityGraphMapper.java:414)
    at org.neo4j.ogm.context.EntityGraphMapper.mapEntity(EntityGraphMapper.java:265)
    at org.neo4j.ogm.context.EntityGraphMapper.map(EntityGraphMapper.java:149)
    at org.neo4j.ogm.session.delegates.SaveDelegate.lambda$save$1(SaveDelegate.java:89)
    at java.util.Collections$SingletonList.forEach(Collections.java:4822)
    at org.neo4j.ogm.session.delegates.SaveDelegate.save(SaveDelegate.java:89)
    at org.neo4j.ogm.session.delegates.SaveDelegate.save(SaveDelegate.java:51)
    at org.neo4j.ogm.session.Neo4jSession.save(Neo4jSession.java:468)
    at Examples.TestNeo4j.main(TestNeo4j.java:41)

I am getting the error only when getting classDescription from the OntologyUtils.getClassDescription method. However, if I instantiate a ResourceDescription newly, I don't get the error. In short, OntologyUtils.getClassDescription calls several other methods to add information to the new instance.

Answer 1

This problem was because the package names contain capital letters. As mentioned in this GitHub issue, package names should be completely in lower case