4

I have a Tomcat server running a servlet using the Jersey 2.6 framework. Within the servlet, I am using Jackson for JSON <--> POJO marshalling. I've recently learned of Moxy and am trying to switch to it, as it seems to be preferred by Jersey.

Currently, I have the following in my POM:

<dependency>
    <groupId>org.glassfish.jersey.media</groupId>
    <artifactId>jersey-media-moxy</artifactId>
    <version>2.6</version>
</dependency>

One of my RESTful services is the following:

 @GET
 @Path("threatSeverities")
 @Produces(MediaType.APPLICATION_JSON)
 public List<String> getThreatSeverities() {
     return dc.selectAllSeverities();
 }

This was working fine with Jackson. When I changed to Moxy, unit tests such as the following:

 @Test
 public void testThreatSeverities() {
     final Response response = target("threatSeverities").request().get();
     List<String> severities = response.readEntity(new GenericType<List<String>> () {});
     assertNotNull(severities);
 }

Would produce the following error:

org.glassfish.jersey.message.internal.MessageBodyProviderNotFoundException: MessageBodyReader not found for media type=text/plain, type=interface java.util.List, genericType=java.util.List<java.lang.String>.
at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor$TerminalReaderInterceptor.aroundReadFrom(ReaderInterceptorExecutor.java:225)
at org.glassfish.jersey.message.internal.ReaderInterceptorExecutor.proceed(ReaderInterceptorExecutor.java:149)
at org.glassfish.jersey.message.internal.MessageBodyFactory.readFrom(MessageBodyFactory.java:1124)
at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:853)
at org.glassfish.jersey.message.internal.InboundMessageContext.readEntity(InboundMessageContext.java:812)
at org.glassfish.jersey.client.ClientResponse.readEntity(ClientResponse.java:377)
at org.glassfish.jersey.client.InboundJaxrsResponse$2.call(InboundJaxrsResponse.java:122)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:228)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:398)
at org.glassfish.jersey.client.InboundJaxrsResponse.readEntity(InboundJaxrsResponse.java:119)
at com.hp.it.scv.mobile.rest.RestTest.testThreatSeverities(RestTest.java:85)
at (... truncated)

Interesting thing to note, even though the controller method getThreatSeverities has a @Produces(MediaType.APPLICATION_JSON), it seems as though Moxy (or something else I do not have visibility into) is changing the Content-Type header of the response to text/plain in the unit tests. None of this was happening with Jackson.

One more thing to note, this seems to be specific with List<String> objects. Moxy marshalls lists of POJOs without issue.

  1. Does Moxy natively support marshalling List<String> objects into JSON strings? It seems as though the answer is no. I couldn't find a conclusive answer online. I am wondering if I need to write my own MessageBodyReader and MessageBodyWriter for List<String> objects.
  2. Does someone know what could be changing the Content-Type header to text/plain when using Moxy? I suspect it is Moxy, maybe because it sees that I am trying to return a simple list of strings.

Update (2/2/2015):

As pointed out by peeskillet, the response returned was a HTTP 500. I was able to extract the stack trace out of the response and was given the following:

Stack trace: javax.ws.rs.WebApplicationException: HTTP 500 Internal Server Error
at org.eclipse.persistence.jaxb.rs.MOXyJsonProvider.writeTo(MOXyJsonProvider.java:810)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.invokeWriteTo(WriterInterceptorExecutor.java:263)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.aroundWriteTo(WriterInterceptorExecutor.java:250)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.server.internal.JsonWithPaddingInterceptor.aroundWriteTo(JsonWithPaddingInterceptor.java:103)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.server.internal.MappableExceptionWrapperInterceptor.aroundWriteTo(MappableExceptionWrapperInterceptor.java:88)
at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
at org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo(MessageBodyFactory.java:1154)
at org.glassfish.jersey.server.ServerRuntime$Responder.writeResponse(ServerRuntime.java:571)
at org.glassfish.jersey.server.ServerRuntime$Responder.processResponse(ServerRuntime.java:378)
at org.glassfish.jersey.server.ServerRuntime$Responder.process(ServerRuntime.java:368)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:262)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:319)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:236)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1028)
at org.glassfish.jersey.grizzly2.httpserver.GrizzlyHttpContainer.service(GrizzlyHttpContainer.java:363)
at org.glassfish.grizzly.http.server.HttpHandler$1.run(HttpHandler.java:217)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:565)
at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:545)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.xml.bind.MarshalException - with linked exception:
[Exception [EclipseLink-25003] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: An error occurred marshalling the object
Internal Exception: Exception [EclipseLink-25007] (Eclipse Persistence  Services - 2.5.0.v20130507-3faac2b):  org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project.  For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.]
at org.eclipse.persistence.jaxb.JAXBMarshaller.marshal(JAXBMarshaller.java:403)
at org.eclipse.persistence.jaxb.rs.MOXyJsonProvider.writeTo(MOXyJsonProvider.java:808)
... 25 more
Caused by: Exception [EclipseLink-25003] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: An error occurred marshalling the object
Internal Exception: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project.  For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.
at org.eclipse.persistence.exceptions.XMLMarshalException.marshalException(XMLMarshalException.java:97)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:911)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:848)
at org.eclipse.persistence.jaxb.JAXBMarshaller.marshal(JAXBMarshaller.java:401)
... 26 more
Caused by: Exception [EclipseLink-25007] (Eclipse Persistence Services - 2.5.0.v20130507-3faac2b): org.eclipse.persistence.exceptions.XMLMarshalException
Exception Description: A descriptor for class java.lang.String was not found in the project.  For JAXB, if the JAXBContext was bootstrapped using TypeMappingInfo[] you must call a marshal method that accepts TypeMappingInfo as an input parameter.
at org.eclipse.persistence.exceptions.XMLMarshalException.descriptorNotFoundInProject(XMLMarshalException.java:139)
at org.eclipse.persistence.internal.oxm.Context$ContextState.getSession(Context.java:143)
at org.eclipse.persistence.oxm.XMLContext$XMLContextState.getSession(XMLContext.java:787)
at org.eclipse.persistence.oxm.XMLContext$XMLContextState.getSession(XMLContext.java:1)
at org.eclipse.persistence.internal.oxm.Context.getSession(Context.java:451)
at org.eclipse.persistence.oxm.XMLContext.getSession(XMLContext.java:356)
at org.eclipse.persistence.oxm.XMLContext.getSession(XMLContext.java:1)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:568)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:1096)
at org.eclipse.persistence.internal.oxm.XMLMarshaller.marshal(XMLMarshaller.java:869)
... 28 more

From Exception Description: A descriptor for class java.lang.String was not found in the project. it seems as though List<String> to JSON marshalling isn't possible without coding something manually.

Derek Overlock
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  • The exception looks to be on the client side. I haven't gotten a chance to test it, so I'm not sure about your first question, but for the second question, it looks like you are using the JerseyTest framework. If you are using the grizzley container. If there is a 500 it will get mapped to a grizzly response that is `text/plain`. You can get the status code from the response to see if it's a 500 – Paul Samsotha Jan 30 '15 at 03:03
  • Good point. I just added `System.out.println(response.getHeaderString("Content-type")); System.out.println(response.getStatus());` and was returned `text-plain 500`. That answers the second question. I'm still left wondering why Moxy can't do a simply `List` to JSON conversion. – Derek Overlock Feb 02 '15 at 19:46
  • moxy can do it, i had some weird errors like that for reasons that didn't seem relevant. please try to include .request(MediaType.APPLICATION_JSON_TYPE) in your test – arisalexis Mar 31 '15 at 11:59

1 Answers1

4

There is some unclear restriction within MOXy code ( moxy/org.eclipse.persistence.moxy/src/org/eclipse/persistence/jaxb/rs/MOXyJsonProvider.java ) which prevents it to process collections of 'java.*' classes. I've filed the issue against this.

https://bugs.eclipse.org/bugs/show_bug.cgi?id=459227

yaroska
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