I have also had similar problems (Websphere 4.0). I think in my case it was because of an excessive number of objects being created and destroyed (i.e., garbage collection tool several seconds). But I never fully diagnosed the problem (And I am not even sure that the problem was due to POI).
I don't know what you mean when you say 'Websphere app server hangs up'. Do you mean that there is no response from the admin console? No response from any servlet? Or just no response from the servlet that creates a HSSFWorkbook? Do you have a load balanced environment? Could session serialization be a problem? (Are you putting the HSSFWorkbook into a HttpSession, and letting Websphere try to persist the session?) Are you trying to send a large spreadsheet to the client with https? You could try the following: 1) Use Websphere's own internal HTTP Server, instead of Apache/IIS/Netscape 2) Lower the amount of heap memory used. See if that makes the lockups more frequent. 3) Turn on Garbage Collection tracing. See if generating the HSSFWorkbook causes many sweeps. I think that Garbage Collection is the most likely culprit. (A JVM can do very little while a garbage collection is in process. That would cause your application to freeze. But the Admin Console and other application servers should continue to respond). If the problem is limited to a single servlet, you might also be synchronizing the servlet object on the request. For example, if there is a servlet that implements SingleThreadModel, (or if you set it up that way in web.xml), then subsequent requests for workbooks will appear to freeze until the first workbook is completely downloaded. -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Sent: Tuesday, January 06, 2004 11:26 AM To: [EMAIL PROTECTED] Subject: Locking up Application Server when creating new HSSFWorkbook We are running into a strange issue on our application. When we are reading in an existing Excel spreadsheet (about 3.5 MB) and creating a new HSSFWorkbook, our entire WebSphere app server hangs up. Once the workbook is created, all is well again. As far as we can tell, there are plenty of system resources available (CPU and memory). The POI version that we are using is 2.0 RC1. Anyone run into a similar problem? Thanks in advance... --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
