Glassfish error when producing JSON

I developed an Android app and now I'm starting with its external DB and its server, the communication is performed by RESTful web services.

This Android aplication just produces and consumes info in JSON, so in my web services facades I just want to erase any mention to XML in the CRUD methods, (automatically generated by NetBeans).

I mean, from this:

@GET
@Override
@Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
public List<Counselor> findAll() {
    return super.findAll();
}

To this (without the MediaType.APPLICATION_XML):

@GET
@Override
@Produces(MediaType.APPLICATION_JSON)
public List<Counselor> findAll() {
    return super.findAll();
}

The thing is that when I deploy these changes in my GlassFish Server (4.1.1) and do some tests with my browser (just want to see my DB data) I get an error with this stacktrace:

java.lang.NoClassDefFoundError: Could not initialize class org.eclipse.persistence.jaxb.BeanValidationHelper
    at org.eclipse.persistence.jaxb.JAXBBeanValidator.isConstrainedObject(JAXBBeanValidator.java:257)
    at org.eclipse.persistence.jaxb.JAXBBeanValidator.shouldValidate(JAXBBeanValidator.java:208)
    at org.eclipse.persistence.jaxb.JAXBMarshaller.validateAndTransformIfNeeded(JAXBMarshaller.java:587)
    at org.eclipse.persistence.jaxb.JAXBMarshaller.marshal(JAXBMarshaller.java:481)
    at org.eclipse.persistence.jaxb.rs.MOXyJsonProvider.writeTo(MOXyJsonProvider.java:949)
    at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$TerminalWriterInterceptor.invokeWriteTo(WriterInterceptorExecutor.java:265)
    at org.glassfish.jersey.message.internal.WriterInterceptorExecutor$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:106)
    at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
    at org.glassfish.jersey.server.internal.MappableExceptionWrapperInterceptor.aroundWriteTo(MappableExceptionWrapperInterceptor.java:86)
    at org.glassfish.jersey.message.internal.WriterInterceptorExecutor.proceed(WriterInterceptorExecutor.java:162)
    at org.glassfish.jersey.message.internal.MessageBodyFactory.writeTo(MessageBodyFactory.java:1130)
    at org.glassfish.jersey.server.ServerRuntime$Responder.writeResponse(ServerRuntime.java:683)
    at org.glassfish.jersey.server.ServerRuntime$Responder.processResponse(ServerRuntime.java:424)
    at org.glassfish.jersey.server.ServerRuntime$Responder.process(ServerRuntime.java:414)
    at org.glassfish.jersey.server.ServerRuntime$2.run(ServerRuntime.java:312)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:271)
    at org.glassfish.jersey.internal.Errors$1.call(Errors.java:267)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:297)
    at org.glassfish.jersey.internal.Errors.process(Errors.java:267)
    at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:317)
    at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:292)
    at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:1139)
    at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:460)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:386)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:334)
    at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:221)
    at org.apache.catalina.core.StandardWrapper.service(StandardWrapper.java:1682)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:318)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:160)
    at org.apache.catalina.core.StandardPipeline.doInvoke(StandardPipeline.java:734)
    at org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:673)
    at com.sun.enterprise.web.WebPipeline.invoke(WebPipeline.java:99)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:174)
    at org.apache.catalina.connector.CoyoteAdapter.doService(CoyoteAdapter.java:416)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:283)
    at com.sun.enterprise.v3.services.impl.ContainerMapper$HttpHandlerCallable.call(ContainerMapper.java:459)
    at com.sun.enterprise.v3.services.impl.ContainerMapper.service(ContainerMapper.java:167)
    at org.glassfish.grizzly.http.server.HttpHandler.runService(HttpHandler.java:206)
    at org.glassfish.grizzly.http.server.HttpHandler.doHandle(HttpHandler.java:180)
    at org.glassfish.grizzly.http.server.HttpServerFilter.handleRead(HttpServerFilter.java:235)
    at org.glassfish.grizzly.filterchain.ExecutorResolver$9.execute(ExecutorResolver.java:119)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeFilter(DefaultFilterChain.java:283)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.executeChainPart(DefaultFilterChain.java:200)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.execute(DefaultFilterChain.java:132)
    at org.glassfish.grizzly.filterchain.DefaultFilterChain.process(DefaultFilterChain.java:111)
    at org.glassfish.grizzly.ProcessorExecutor.execute(ProcessorExecutor.java:77)
    at org.glassfish.grizzly.nio.transport.TCPNIOTransport.fireIOEvent(TCPNIOTransport.java:536)
    at org.glassfish.grizzly.strategies.AbstractIOStrategy.fireIOEvent(AbstractIOStrategy.java:112)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.run0(WorkerThreadIOStrategy.java:117)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy.access$100(WorkerThreadIOStrategy.java:56)
    at org.glassfish.grizzly.strategies.WorkerThreadIOStrategy$WorkerThreadRunnable.run(WorkerThreadIOStrategy.java:137)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.doWork(AbstractThreadPool.java:591)
    at org.glassfish.grizzly.threadpool.AbstractThreadPool$Worker.run(AbstractThreadPool.java:571)
    at java.lang.Thread.run(Thread.java:745)

Any idea about this?

I hope I explain myself...thanks in advance!!

It's a bug in Glassfish 4.1.1 https://java.net/jira/browse/JERSEY-2888

I was able to fix it in a dirty way:

In glassfish/modules/org.eclipse.persistence.moxy.jar fix META-INF/MANIFEST.MF Just append the following to Import-Package:

,org.xml.sax.helpers,javax.xml.parsers;resolution:=optional,javax.naming;resolution:=optional

so it looks like after:

and restart GF

btw: you can easy edit jars in terminal with

emacs org.eclipse.persistence.moxy.jar

Jack's answer is really helpful.
It pinpoints the problem and was useful when there was no patch.

But I suggest instead of editing the jar, since the bug is corrected in 2.6.1, to download it at : org.eclipse.persistence.moxy-2.6.1 from MVNRepository

OR get the latest version from MVNRepository: https://mvnrepository.com/artifact/org.eclipse.persistence/org.eclipse.persistence.moxy

and replace it.
Don't forget to close and reopen you IDE.