Problem with Tomcat hangs for no obvious reason

["Mingus, Jennifer (JC)" <JC...@dow.com>]

Hi, 

I have tomcat 5.5.23 installed on Red Hat Enterprise Linux 5 and a simple web application using JSF/AJAX. The web application only has two pages. In the first page, it has a few dropdown lists, which get the options from a SQL server database. The last dropdown list is refreshed when selections on the others changed. There are two buttons: reset and ok. Click reset to reset all dropdownlist. And when the user click ok, it goes to the next page to confirm the choices the user made. Then after click on a button on the second page, the code will simply write a text file to the server. 

The problem I'm having is that after a few submissions, the last dropdown list won't refresh. Then no clicks will get a response. And I can even not go to the manager page. Tomcat just hangs. And there is no error printed out at catalina.out or localhost.log. I've checked and made sure that all connections to the database is closed. I found on google that if tomcat is installed on Redhat 9, you need to put export LD_ASSUME_KERNEL=2.4.1 to catalina.sh. But I'm using Red hat Enterprise linux 5. However, I tried it anyway and it didn't work. One thing I noticed when I start up tomcat is that I always get "The Apache Tomcat Native library which allows optional performance in production environments was not found on the java.library.path". Should I install the library? I didn't think it'll cause Tomcat to hang though.

So, my question is whether this is caused by tomcat installation and configuration on the environment or it is caused by the JSF implementation. Will some code in JSF cause tomcat to hang? I would think if it's a bug in the web application, it will just cause the application not working, not tomcat to be not responsive at all. How can I find out the reason and how can I fix it? I'm new with JSF also. I inherited these couple pages from somebody else.

Any suggestions will be greatly appreciated. 

Thanks, 
Jennifer 

Re: Problem with Tomcat hangs for no obvious reason

[David Smith <dn...@cornell.edu>]

I'm wondering if the Ajax is consuming the two or so connections your 
browser allows so all other calls to the server get blocked.  If you 
close all your browser windows and re-launch IE, does tomcat start 
responding again?  If so, tomcat isn't hanging -- it's a javascript 
issue with your client.

--David

Mingus, Jennifer (JC) wrote:
> Hi, 
>
> I have tomcat 5.5.23 installed on Red Hat Enterprise Linux 5 and a simple web application using JSF/AJAX. The web application only has two pages. In the first page, it has a few dropdown lists, which get the options from a SQL server database. The last dropdown list is refreshed when selections on the others changed. There are two buttons: reset and ok. Click reset to reset all dropdownlist. And when the user click ok, it goes to the next page to confirm the choices the user made. Then after click on a button on the second page, the code will simply write a text file to the server. 
>
> The problem I'm having is that after a few submissions, the last dropdown list won't refresh. Then no clicks will get a response. And I can even not go to the manager page. Tomcat just hangs. And there is no error printed out at catalina.out or localhost.log. I've checked and made sure that all connections to the database is closed. I found on google that if tomcat is installed on Redhat 9, you need to put export LD_ASSUME_KERNEL=2.4.1 to catalina.sh. But I'm using Red hat Enterprise linux 5. However, I tried it anyway and it didn't work. One thing I noticed when I start up tomcat is that I always get "The Apache Tomcat Native library which allows optional performance in production environments was not found on the java.library.path". Should I install the library? I didn't think it'll cause Tomcat to hang though.
>
> So, my question is whether this is caused by tomcat installation and configuration on the environment or it is caused by the JSF implementation. Will some code in JSF cause tomcat to hang? I would think if it's a bug in the web application, it will just cause the application not working, not tomcat to be not responsive at all. How can I find out the reason and how can I fix it? I'm new with JSF also. I inherited these couple pages from somebody else.
>
> Any suggestions will be greatly appreciated. 
>
> Thanks, 
> Jennifer 
>
>
>   


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