Asynchronous Servlet: dispatching to jsp causes endless loop

[ceiching]

In JBoss 7.1.1.GA with JBossWeb 7.0.13.GA the dispatching of an asynchronous servlet request to a JSP causes and endless loop. This can be reproduced by installing the attached AsyncServletTest.war and executing the following link: http://localhost:8080/AsyncServletTest/AsyncServlet

This results in an output similar to:

15:34:27,966 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor start: 1358433267966

15:34:28,981 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor end: 1358433268981

15:34:28,981 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 start: 1358433268981

15:34:29,996 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 end: 1358433269996

15:34:29,996 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 start: 1358433269996

15:34:31,011 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 end: 1358433271011

15:34:31,011 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 start: 1358433271011

15:34:32,026 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 end: 1358433272026

15:34:32,026 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 start: 1358433272026

15:34:33,041 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 end: 1358433273041

15:34:33,041 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 start: 1358433273041

15:34:34,056 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 end: 1358433274056

15:34:34,056 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 start: 1358433274056

15:34:35,071 INFO  [stdout] (http--127.0.0.1-8080-1) AsyncProcessor1 end: 1358433275071

...

This only happens when dispatching to a JSP (line 60):

10 AsyncContext ac = ...

20 System.out.println("AsyncProcessor1 start: " + System.currentTimeMillis());

30 ServletRequest req = ac.getRequest();

40 // do something    

50 req.setAttribute("result", result);

60 ac.dispatch("/result.jsp");

70 System.out.println("AsyncProcessor1 end: " + System.currentTimeMillis());

Any clues why this happens?

[jfclere]

I think if you read the http://docs.oracle.com/javaee/6/api/javax/servlet/AsyncContext.html#dispatch%28java.lang.String%29 you will see you need to start your AsyncProcessor() on one event (probably onStartAsync()).

What are you trying to do?

[ceiching]

Hi Jean-Frederic,

I'm currently testing the Servlet 3.0 implementation of the different app servers and thus tried to set up a sample test case which:

(1) starts a worker using AsyncContext.start(AsyncProcessor)

(2) stats another worker with AsyncContext.start(AsyncProcessor1)

(3) dispatching to a jsp for rendering the result with AsyncContext.dispatch(path to jsp)

i.e. I do only one dispatch on the AsyncContext as specified in the JavaDoc. If I change the example to render the result directly in worker1 completing with AsyncContext.complete(), the processing is done correctly. However, as soon as the dispatch to the JSP is added, the loop occurs.

So far the sample worked fine with GlassFish 310, WebSphere 8.5, WebLogic 12.1.1. and Tomcat 7.0.33.

THX for your time, Christian

[jfclere]

it might be a bug then :-(

[ceiching]

Ok, thank you. I filed an issue (JBWEB-260).

[ceiching]

JBWEB-260 is fixed. Checked briefly with Wildfly 8 Alpha 3 (uses jbossweb-8.0.0.Alpha1) - works fine.