Hi,
> ... I believe that you should not declare objects that will have dynamic data
> outside of the method that is using them. I removed the declaration from
>the class level and declared the Result Bean in the doGet method where
>it is used. Now I can have as many web browser executing at the same
>time and all displaying the correct information. ...
I got the same "result :-) " from my testing, and I just try to add a note, I am
sorry some of the following have already been explained in several emails,
I just want to explain it more clear :-)
0 for the servlet engine which only make ONE instance for
"our custom servlet class" -- normally(I guess) :
a -- for "static class variable"
[a] all the "static class variable" will be "shared" to all
new threads -- and to all "client reauestings" , this is
because now we have only one "custom servlet
class" .
[b] So we can not use it as "dynamic data" which is
different to every "client requesting".
[c] But we can use it to lock our code between those threads.
b -- for "not_static class variable"
[a] all the "not_static class variable" will be "shared" to all
new threads -- and to all "client reauestings" , this is
because now we have only one instance.
[b] So we can not use it as "dynamic data" which is
different to every "client requesting".
[c] But we also can use it to lock our code between those threads.
c -- for "method variable"
[a] all the "method variable" will NOT be "shared" to all
new threads -- and NOT to all "client reauestings" I guess
this is
because every new thread will use its own "copy"
for these "method variable"
[b] So we can use it as "dynamic data" which is
different to every "client requesting".
[c] But we can NOT use it to lock our code between those threads.
1 for the servlet engine which will make "instance pool" for
"our custom servlet class" , I don't know :-) But it seems
that now these instances are "independent:-) ", if So, I
guess 0-a and 0-c are still right, but 0-b is not right.
Bo
OCT.12, 2000
Marc Krisjanous wrote:
> Hi all,
>
> once again thank you for your comments about exception handling. I have now
> revised by strategy.
>
> One thing I would like to share with you is:
>
> I had a simple servlet that accepts a parameter from a requesting page, it
> then adds the parameter to a Result Bean, the bean is then added to the
> session object. A JSP page was then called. The JSP page then displayed
> the results by accessing the Result bean and extracting the parameter value.
> It worked. Now I had 3 web browsers loaded on my machine and added
> different values to each text box (one per web page). I then executed the 3
> Web Pages at the same time. Well! the results were different! Sometimes all
> pages showed the same result and sometimes 2 would etc... It took me a
> while to understand what had happened; I add declared by Result bean at the
> class level - outside of a method. I believe that you should not declare
> objects that will have dynamic data outside of the method that is using
> them. I removed the declaration from the class level and declared the
> Result Bean in the doGet method where it is used. Now I can have as many
> web browser executing at the same time and all displaying the correct
> information.
>
> Am I correct in my assumptions - it seems very fundamental.
>
> Best Regards
>
> Marc
>
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