Hi,
From the stack trace, this looks like a tomcat problem to me.
Marek
> On 24 Jun 2015, at 00:32, ahar_ <adamh137_at_gmail.com> wrote:
>
> I have implemented an SSE Restful web interface for publishing messages
> received from an internal JMS queue out to external clients. I have managed
> to get a test message out to a Java client, but the Thread throws a null
> pointer exception before completing the write() execution, closing the
> connection and preventing further communication.
>
> *Here is my resource class:*
>
> @GET
> @Path("/stream_data")
> @Produces(SseFeature.SERVER_SENT_EVENTS)
> public EventOutput getServerSentEvents(@Context ServletContext context){
> final EventOutput eventOutput = new EventOutput();
> MService mService = (MService) context.getAttribute("instance");
> new Thread( new ObserverThread(eventOutput, mService) ).start();
> return eventOutput;
> }
>
> *And here is my thread's run method:*
>
> public class ObserverThread implements Observer, Runnable {
> //constructor sets eventOutput & mService objects
> public void run() {
> try {
> String message = "{'symbol':'test','entryType'='0','price'='test'}";
> Thread.sleep(1000);
> OutboundEvent.Builder builder = new OutboundEvent.Builder();
> builder.mediaType(MediaType.APPLICATION_JSON_TYPE);
> builder.data(String.class, message);
> OutboundEvent event = builder.build();
> eventOutput.write(event);
> System.out.println(">>>>>>SSE CLIENT HAS BEEN REGISTERED!");
> mService.addObserver(this);
> while(!eventOutput.isClosed()){
> if(!updatesQ.isEmpty()){
> pushUpdate(updatesQ.dequeue());
> }
> }
> System.out.println("<<<<<<<SSE CLIENT HAS BEEN DEREGISTERED!");
> } catch (IOException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> } catch (InterruptedException e) {
> // TODO Auto-generated catch block
> e.printStackTrace();
> }
> }
>
> <b>Here is my client code:*
>
> Client client =
> ClientBuilder.newBuilder().register(SseFeature.class).build();
> WebTarget target = client.target(url);
> EventInput eventInput = target.request().get(EventInput.class);
> try {
> while (!eventInput.isClosed()) {
> eventInput.setChunkType(MediaType.WILDCARD_TYPE);
> final InboundEvent inboundEvent = eventInput.read();
> if (inboundEvent != null) {
> String theString = inboundEvent.readData();
> System.out.println(theString + "\n");
> }
> }
> } catch (Exception e) {
> e.printStackTrace();
> }
> I am getting the "{'symbol':'test','entryType'='0','price'='test'}" test
> message printed to the client console, but the server then prints a
> NullPointerException before it can print the ">>>>SSE Client registered"
> message. This closes the connection so the client exits the while loop and
> stops listening for updates.
>
> I am not sure why the nullpointer is being thrown within the write method,
> it seems to be something related to flushing the buffer to await another
> chunk, shown in the stack trace:
>
> Exception in thread "Thread-20" java.lang.NullPointerException
> at
> org.apache.coyote.http11.InternalOutputBuffer.realWriteBytes(InternalOutputBuffer.java:741)
> at org.apache.tomcat.util.buf.ByteChunk.flushBuffer(ByteChunk.java:434)
> at
> org.apache.coyote.http11.InternalOutputBuffer.flush(InternalOutputBuffer.java:299)
> at org.apache.coyote.http11.Http11Processor.action(Http11Processor.java:981)
> at org.apache.coyote.Response.action(Response.java:183)
> at org.apache.catalina.connector.OutputBuffer.doFlush(OutputBuffer.java:314)
> at org.apache.catalina.connector.OutputBuffer.flush(OutputBuffer.java:288)
> at
> org.apache.catalina.connector.CoyoteOutputStream.flush(CoyoteOutputStream.java:98)
> at
> org.glassfish.jersey.message.internal.CommittingOutputStream.flush(CommittingOutputStream.java:292)
> at org.glassfish.jersey.server.ChunkedOutput$1.call(ChunkedOutput.java:241)
> at org.glassfish.jersey.server.ChunkedOutput$1.call(ChunkedOutput.java:192)
> at org.glassfish.jersey.internal.Errors.process(Errors.java:315)
> at org.glassfish.jersey.internal.Errors.process(Errors.java:242)
> at
> org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:345)
> at
> org.glassfish.jersey.server.ChunkedOutput.flushQueue(ChunkedOutput.java:192)
> at org.glassfish.jersey.server.ChunkedOutput.write(ChunkedOutput.java:182)
> at com.bpc.services.service.ObserverThread.run(MarketObserverThread.java:32)
> at java.lang.Thread.run(Thread.java:745)
>
>
>
>
> --
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