Answered there.

On Wed, Aug 6, 2014 at 11:22 AM, Rubin <[email protected]> wrote:

> I posted this question on stack overflow too:
>
>
> http://stackoverflow.com/questions/25141511/neo4j-cypher-results-as-json-getting-jsonmappingexception-when-using-jsonhelper
>
>
> Regards,
>
> On 05-08-14 15:31, Rubin wrote:
> > Hi Neo4j,
> >
> > Me and my team are working on neo4vertx, a module that makes it possible
> > to talk to a Neo4j database using Vert.x.
> >
> > We are implementing a feature called "query" which allows a Vert.x user
> > to send a Cypher query as an eventbus message and get a JSON resultset
> > back.
> >
> > However, we seem to run into an unexpected problem when serializing to
> > JSON using JsonHelper.createJsonFrom() with certain queries.
> >
> > A quick example (database has stuff in it of course):
> >
> > // Fails with JsonMappingException (see below):
> > "MATCH (n) RETURN n"
> >
> > //Succeeds:
> > "MATCH (n) RETURN n.something"
> >
> > //Rest of code:
> > engine = new ExecutionEngine(graphDatabaseService);
> > ExecutionResult result;
> > result = engine.execute(query);
> >
> > Object object = result.iterator();
> > String foo = JsonHelper.createJsonFrom(object);
> > System.out.println("DEBUG (foo): " + foo);
> >
> >
> > Does this look familiar to anyone? We essentially want to be able to
> > send any kind of query and either return an empty json string or a json
> > representation not unlike the result.json that you can retrieve from the
> > web interface of neo4j!
> >
> >
> > The Exception:
> > testQuery(org.openpcf.neo4vertx.neo4j.Neo4jGraphTest)  Time elapsed:
> > 2.362 sec  <<< ERROR!
> > org.neo4j.server.rest.domain.JsonBuildRuntimeException:
> > org.codehaus.jackson.map.JsonMappingException: No serializer found for
> > class
> > org.neo4j.kernel.InternalAbstractGraphDatabase$DependencyResolverImpl
> > and no properties discovered to create BeanSerializer (to avoid
> > exception, disable SerializationConfig.Feature.FAIL_ON_EMPTY_BEANS) )
> > (through reference chain:
> >
> scala.collection.convert.MapWrapper["content"]->org.neo4j.kernel.impl.core.NodeProxy["graphDatabase"]->org.neo4j.test.["dependencyResolver"])
> >       at
> >
> org.codehaus.jackson.map.ser.impl.UnknownSerializer.failForEmpty(UnknownSerializer.java:52)
> >       at
> >
> org.codehaus.jackson.map.ser.impl.UnknownSerializer.serialize(UnknownSerializer.java:25)
> >       at
> >
> org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446)
> >       at
> >
> org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150)
> >       at
> >
> org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112)
> >       at
> >
> org.codehaus.jackson.map.ser.BeanPropertyWriter.serializeAsField(BeanPropertyWriter.java:446)
> >       at
> >
> org.codehaus.jackson.map.ser.std.BeanSerializerBase.serializeFields(BeanSerializerBase.java:150)
> >       at
> >
> org.codehaus.jackson.map.ser.BeanSerializer.serialize(BeanSerializer.java:112)
> >       at
> >
> org.codehaus.jackson.map.ser.std.MapSerializer.serializeFields(MapSerializer.java:262)
> >       at
> >
> org.codehaus.jackson.map.ser.std.MapSerializer.serialize(MapSerializer.java:186)
> >       at
> >
> org.codehaus.jackson.map.ser.std.MapSerializer.serialize(MapSerializer.java:23)
> >       at
> >
> org.codehaus.jackson.map.ser.std.StdContainerSerializers$IteratorSerializer.serializeContents(StdContainerSerializers.java:234)
> >       at
> >
> org.codehaus.jackson.map.ser.std.StdContainerSerializers$IteratorSerializer.serializeContents(StdContainerSerializers.java:195)
> >       at
> >
> org.codehaus.jackson.map.ser.std.AsArraySerializerBase.serialize(AsArraySerializerBase.java:86)
> >       at
> >
> org.codehaus.jackson.map.ser.StdSerializerProvider._serializeValue(StdSerializerProvider.java:610)
> >       at
> >
> org.codehaus.jackson.map.ser.StdSerializerProvider.serializeValue(StdSerializerProvider.java:256)
> >       at
> org.codehaus.jackson.map.ObjectMapper.writeValue(ObjectMapper.java:1613)
> >       at
> >
> org.neo4j.server.rest.domain.JsonHelper.createJsonFrom(JsonHelper.java:108)
> >       at
> org.openpcf.neo4vertx.neo4j.Neo4jGraph.query(Neo4jGraph.java:132)
> >       at
> >
> org.openpcf.neo4vertx.neo4j.Neo4jGraphTest.testQuery(Neo4jGraphTest.java:47)
> >
>
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