[jetty-users] Jetty Continuations NullPointerException

[fmiguelf@xxxxxx]

Hi All,

I'm trying to make a simple Continuations test but I can't get it to work. The objective is simple, flush a "Hello World" string to the client every 2 seconds.
 

import java.lang.Exception;

import java.io.IOException;

import java.io.PrintWriter;

 

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

 

import org.eclipse.jetty.server.Server;

import org.eclipse.jetty.servlet.ServletContextHandler;

import org.eclipse.jetty.servlet.ServletHolder;

import org.eclipse.jetty.util.thread.QueuedThreadPool;

import org.eclipse.jetty.continuation.Continuation;

import org.eclipse.jetty.continuation.ContinuationSupport;

 

class Test

{

    public static void main(String[] args) throws Exception

    {

        Server server = new Server(8080);

        ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);

        context.setContextPath("/");

        context.addServlet(new ServletHolder(new ContinuationServlet()),"/*");

        server.setHandler(context);

        server.start();

        server.join();

    }

 

    static class ContinuationServlet extends HttpServlet

    {

        @Override

        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException

        {

            Continuation continuation = ContinuationSupport.getContinuation(request);

            response.setContentType("text/html;charset=utf-8");

            response.setStatus(HttpServletResponse.SC_OK);

            PrintWriter writer = response.getWriter();

            writer.println("Hello World");

            writer.flush();

            continuation.setTimeout(2000);

            continuation.suspend();

        }

    }

}

 

The code works up until the servlet tries to prinln the second time, throwing a NullPointerException. Any hint on what I'm doing wrong?
 

[java] java.lang.NullPointerException

     [java] at org.eclipse.jetty.io.BufferUtil.putHexInt(BufferUtil.java:132)

     [java] at org.eclipse.jetty.http.HttpGenerator.prepareBuffers(HttpGenerator.java:994)

     [java] at org.eclipse.jetty.http.HttpGenerator.flushBuffer(HttpGenerator.java:824)

     [java] at org.eclipse.jetty.http.AbstractGenerator.flush(AbstractGenerator.java:452)

     [java] at org.eclipse.jetty.server.HttpOutput.flush(HttpOutput.java:94)

     [java] at org.eclipse.jetty.server.HttpConnection$Output.flush(HttpConnection.java:1009)

     [java] at org.eclipse.jetty.server.HttpWriter.flush(HttpWriter.java:87)

     [java] at org.eclipse.jetty.io.UncheckedPrintWriter.flush(UncheckedPrintWriter.java:152)

     [java] at Test$ContinuationServlet.doGet(Unknown Source)

     [java] at javax.servlet.http.HttpServlet.service(HttpServlet.java:707)

     [java] at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)

     [java] at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:547)

     [java] at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:480)

     [java] at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:225)

     [java] at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:940)

     [java] at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:409)

     [java] at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:186)

     [java] at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:874)

     [java] at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:117)

     [java] at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:110)

     [java] at org.eclipse.jetty.server.Server.handleAsync(Server.java:390)

     [java] at org.eclipse.jetty.server.HttpConnection.handleRequest(HttpConnection.java:446)

     [java] at org.eclipse.jetty.server.AsyncHttpConnection.handle(AsyncHttpConnection.java:49)

     [java] at org.eclipse.jetty.io.nio.SelectChannelEndPoint.handle(SelectChannelEndPoint.java:586)

     [java] at org.eclipse.jetty.io.nio.SelectChannelEndPoint$1.run(SelectChannelEndPoint.java:44)

     [java] at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:598)

     [java] at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:533)

     [java] at java.lang.Thread.run(Thread.java:680)

Regards,

Miguel