Connection and resource pooling (including thread and instance pooling) is a key value proposition of modern application servers like GlassFish and WebLogic to significantly boost scalability (in fact, WebLogic has long had significantly richer pooling features than GlassFish). While most in the Java EE community take this for granted, many other less mature and robust server-side platforms lack this feature. Indeed, many newcomers to Java EE do not seem to quite grasp connection pooling, even database connection pools. Andy Overton of C2B2 consulting comes to the rescue!
In a very written recent blog entry, Andy explains the basics of database connection pools, demonstrates step-by-step how to setup a connection pool in GlassFish a few different ways and discusses some key configuration options such as pool sizing along with outlining some best practices. It is well worth a read if you are a GlassFish or Java EE fan!