> From: Curtis Garman [mailto:curt.gar...@gmail.com] > Subject: tomcat 5.5.25 shared lib and sharing webapp jars > > I've got a question about the tomcat 5.5.25 shared lib...is there any > danger of using this almost exclusively if you have a lot of jars that > are shared among apps.
The danger is that you have essentially glued all your webapps together, and you may not be able to manipulate (stop/redeploy/start) them individually without serious impacts to the heap, especially PermGen. > I know you can but I also saw something somewhere and now again > (http://www.digitalsanctum.com/2007/08/18/20-tips-for-using-tomcat-in- > production/ > - number 6) about garbage collection only operating on memory that was > inside the scope of a specific app and because the shared lib stuff > doesn't belong to specific app it wouldn't get cleaned up. That's not really what it says. GC knows nothing about the individual webapps; it operates on the Java heap as a whole. The problem with sharing libraries is that they can very easily retain references to caller's objects and thereby prevent the calling classes from ever being unloaded when a webapp is redeployed. > I've got a jvm in development that has about 20 apps in it...to reduce > the heap size, I moved as many jars as I could to the shared lib > folder... Probably a bad idea. Given the extremely low cost of RAM and the widespread availability of 64-bit operating environments, you are likely practicing false economy. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
