NullPointerException when Accept is empty

java.lang.NullPointerException
at org.jboss.resteasy.plugins.server.servlet.HttpServletResponseHeaders.putResponseHeader(HttpServletResponseHeaders.java:167)
at org.jboss.resteasy.plugins.server.servlet.HttpServletResponseHeaders.putAll(HttpServletResponseHeaders.java:157)
at org.jboss.resteasy.core.ServerResponseWriter.commitHeaders(ServerResponseWriter.java:397)
at org.jboss.resteasy.core.ServerResponseWriter$1.commit(ServerResponseWriter.java:123)
at org.jboss.resteasy.util.CommitHeaderOutputStream.commit(CommitHeaderOutputStream.java:50)
at org.jboss.resteasy.util.CommitHeaderOutputStream.write(CommitHeaderOutputStream.java:70)
at org.jboss.resteasy.util.DelegatingOutputStream.write(DelegatingOutputStream.java:48)
at com.fasterxml.jackson.core.json.UTF8JsonGenerator._flushBuffer(UTF8JsonGenerator.java:2039)
at com.fasterxml.jackson.core.json.UTF8JsonGenerator.flush(UTF8JsonGenerator.java:1051)
at com.fasterxml.jackson.databind.ObjectWriter.writeValue(ObjectWriter.java:953)
at org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider.writeTo(ResteasyJackson2Provider.java:240)
at org.jboss.resteasy.core.interception.jaxrs.AbstractWriterInterceptorContext.writeTo(AbstractWriterInterceptorContext.java:137)
at org.jboss.resteasy.core.interception.jaxrs.ServerWriterInterceptorContext.writeTo(ServerWriterInterceptorContext.java:61)
at org.jboss.resteasy.core.interception.jaxrs.AbstractWriterInterceptorContext.proceed(AbstractWriterInterceptorContext.java:124)
at org.jboss.resteasy.core.ServerResponseWriter.writeNomapResponse(ServerResponseWriter.java:141)
at org.jboss.resteasy.core.SynchronousDispatcher.writeResponse(SynchronousDispatcher.java:473)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:422)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:209)
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:227)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:847)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:295)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:214)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:231)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:149)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:512)