Hello, Is using singleton patterns in Tomcat (in servlets programming and deploying them in tomcat) a really bad idea?? I came accross many forum posts and wikis that warn about of OOM errors. One really useful post is http://wiki.apache.org/tomcat/OutOfMemory http://wiki.apache.org/tomcat/OutOfMemory and this is really worth taking a look!! We are having a web application and have four or five singleton patterns, they are really necessary as singletons patterns, such as Xml parsers and Applications properties reader. I have some questions when they say. "server being unable to reclaim the space for the entire webapp class loader".
1) Will I be getting OOM errors only when I redeploy a war file (with singleton patterns) several times without re-starting my Tomcat? Or I will be getting the OOM errors even if I didnot redeploy the war file and the server crashes after some days?? 2) I dont think we can GC a conventional singleton pattern by using a ServletContextListener, as the private instance variable is hard coded and we cannot access it from outside(and set it to null) as its never visible to the outside world unless we try using reflection?? The link that I posted has a reference to apache.commons DiscoverSingleton for Singleton patterns. I have not tried that in my web applications. Will that help me?? instead of using the conventional singleton pattern?? Any suggestion is highly appreciated Thanks in advance jkv -- View this message in context: http://old.nabble.com/Singletons-in-Tomcat%286.0%29-tp26591346p26591346.html Sent from the Tomcat - User mailing list archive at Nabble.com. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
