when exactly response is commited?

[ankur rathi]

a.jsp
-----
 
<%
 
System.out.println("Before forwarding request first time");
 
out.println("Writing in response in a.jsp");
 
RequestDispatcher rd = request.getRequestDispatcher("/b.jsp");
rd.forward(request, response);
 
System.out.println("Still executing service() method");
 
System.out.println("Before forwarding request second time");
 
rd.forward(request, response);
 
System.out.println("After forwarding request second time");
 
%>
 
b.jsp
-----
 
 
<%
 
System.out.println("After forward has happened");
 
out.println("Welcome, you are coming from a.jsp");
 
System.out.println("After writing in response in b.jsp");
 
%>
 
output on console:
-----------------
 
Before forward
After forward has happened
After writing in response in b.jsp
Still executing service() method
Before forwarding request second time
 

It shows an IllegalStateException on browser.
Why because response is commited before forwarding second time.

But where exactly response is commited???
I never called flush() method and the second way is if buffer automatically fills then it writes content to stream (sent information to client), but I don't think that buffer is filled here...

(And if stream is unbuffered then it would have given error at the first forward itself, but this is also not the case)


Thanks.
[ May 26, 2006: Message edited by: Bear Bibeault ]

[Manesh Kumar]

I think JSP compiler generates the code to commit the response at the end of service method. So when you forward for the second time, the forward method throws IllegalStateException since the response is committed.

We never do ourselves of commiting the response, it usually taken care by the container.

[ankur rathi]

Originally posted by Dilip Kumar Jain:
I think JSP compiler generates the code to commit the response at the end of service method. So when you forward for the second time, the forward method throws IllegalStateException since the response is committed.

We never do ourselves of commiting the response, it usually taken care by the container.

If container generate 'response commiting code' just before the end of service() method then this code anyway will be executed after 'second time forward code'...

[Manesh Kumar]

before the end of service code

I meant for sevice() menthod second jsp file (b.jsp).

After forwarding for the first time to b.jsp (the response will be commited after this), The execution will resume in service method of a.jsp. The second call to forward method will throw an IllegalStateException , resulting halt in execution of service method in a.jsp.

I think this clears your doubt.

[ankur rathi]

Originally posted by Dilip Kumar Jain:

I meant for sevice() menthod second jsp file (b.jsp).

After forwarding for the first time to b.jsp (the response will be commited after this), The execution will resume in service method of a.jsp. The second call to forward method will throw an IllegalStateException , resulting halt in execution of service method in a.jsp.

I think this clears your doubt.

Thanks Dilip.
Got it.