title: Glassfish error when producing JSON
body: <p>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.</p>
  
  <p>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).</p>
  
  <p>I mean, from this:</p>
  
  <pre><code>@GET
  @Override
  @Produces({MediaType.APPLICATION_XML, MediaType.APPLICATION_JSON})
  public List&lt;Counselor&gt; findAll() {
      return super.findAll();
  }
  </code></pre>
  
  <p>To this (without the MediaType.APPLICATION_XML):</p>
  
  <pre><code>@GET
  @Override
  @Produces(MediaType.APPLICATION_JSON)
  public List&lt;Counselor&gt; findAll() {
      return super.findAll();
  }
  </code></pre>
  
  <p>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:</p>
  
  <pre><code>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)
  </code></pre>
  
  <p>Any idea about this?</p>
  
  <p>I hope I explain myself...thanks in advance!!</p>