If you implement the SingleThreadModel interface for your Servlet class, TomCat will create a new instance for each request.
Albert -----Original Message----- From: kwirirai [mailto:[EMAIL PROTECTED] Sent: Monday, February 09, 2004 2:12 PM To: Tomcat Users List Subject: Re: Servlet thread safety in Tomcat But if I am to synchronise my code blocks won't that slow done the application, or is there a "mode" that you can put Tomcat into so that it will create a new instance servlet thread with its own variables and execution space and stuff like that .Because I was thinking putting all those synchronized blocks will slow down the app. David Ramsey wrote: >Your primary mistake seems to be in assuming that Tomcat will create a >new instance of a servlet for every thread started. This is not what >happens, therefore servlet instance variables are not thread safe >unless you take additional actions to make them safe. Likewise, >application global entities, such as singletons, won't be thread safe >without taking additional actions on your part. The short rule is >simply if two threads might access this data concurrently, then you >need to protect yourself from such a collision. About the only thing >that is mostly thread safe are objects whose scope is limited to a >single method, but even these can get you in trouble if you put >references to those objects in global locations (such as an application >wide cache). > > >--- kwirirai <[EMAIL PROTECTED]> wrote: > > >>The app is simply meant to grab some mails from a pop server and >>simply >>display it using Java Mail. >>I realise part of my mistake is using global variables >>,unsynchronized >>collections and unsynchronized code blocks.I am not using the single >>thread model. >>My initial thought ( :-) forgive me its some time since I have coded >> >>servlets) was that Tomcat will create a new servlet instance that is >>totally independed of the other, for each request.On testing the app >>on >>two client machines I have realized that the data is corrupted all >>mixed >>up and my velocity template is throwing an error caused by >>concurrent >>modification. >>My question is there some way of making this app thread safe and also >> >>how does Tomcat actually many requests , in terms of the threading >>method used?I am using Tomcat 4.1 >> >> >>Shapira, Yoav wrote: >> >> >> >>>Howdy, >>>State your specific requirements and we can help you design >>>servlets/objects that will meet those requirements. Your original >>> >>> >>post >> >> >>>is too broad to solicit a detailed response. >>> >>>Yoav Shapira >>>Millennium ChemInformatics >>> >>> >>> >>> >>> >>> >>>>-----Original Message----- >>>>From: kwirirai [mailto:[EMAIL PROTECTED] >>>>Sent: Monday, February 09, 2004 12:48 PM >>>>To: [EMAIL PROTECTED] >>>>Subject: Servlet thread safety in Tomcat >>>> >>>>Hi All >>>>I am developing an application that uses JavaMail.What I am >>>> >>>> >>concered is >> >> >>>>the issue of thread safety,and efficiency.My question is do I need >>>> >>>> >>to >> >> >>>>employ synchronized blocks in my Servlet code or is there another >>>> >>>> >>way >> >> >>>> >>>> >>>> >>>> >>>to >>> >>> >>> >>> >>>>implement thread safety.I have been experimenting with the >>>> >>>> >>application >> >> >>>>and I have seen that the data is actualy mixing up.I realy need to >>>> >>>> >>now >> >> >>>>how Tomcat handles request and issues those request ,this is in >>>>connection with threading. I have thought about the single thread >>>> >>>> >>model >> >> >>>>in my servlets but I think this is an inefficient method to use. >>>> >>>>Thanks >>>>Kwiri >>>> >>>> >>>> >>>> >>>> >>>> >>>--------------------------------------------------------------------- >>> >>> >>>>To unsubscribe, e-mail: [EMAIL PROTECTED] >>>>For additional commands, e-mail: >>>> >>>> >>[EMAIL PROTECTED] >> >> >>>> >>>> >>>> >>>> >>> >>> >>>This e-mail, including any attachments, is a confidential business >>> >>> >>communication, and may contain information that is confidential, >>proprietary and/or privileged. This e-mail is intended only for the >>individual(s) to whom it is addressed, and may not be saved, copied, >>printed, disclosed or used by anyone else. If you are not the(an) >>intended recipient, please immediately delete this e-mail from your >>computer system and notify the sender. Thank you. >> >> >>> >>> >>--------------------------------------------------------------------- >> >> >>>To unsubscribe, e-mail: [EMAIL PROTECTED] >>>For additional commands, e-mail: [EMAIL PROTECTED] >>> >>> >>> >>> >>> >>> >> >> > > >__________________________________ >Do you Yahoo!? >Yahoo! Finance: Get your refund fast by filing online. >http://taxes.yahoo.com/filing.html > >--------------------------------------------------------------------- >To unsubscribe, e-mail: [EMAIL PROTECTED] >For additional commands, e-mail: [EMAIL PROTECTED] > > > > --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
