What does it mean for a web application to be "distributable?"

Question

To be more specific, I'm studying sessions, and I'm reading about the <distributable> tag in the deployment descriptor (for example). The text states,

"...it is possible - for the sake of load balancing of fail-over or both - to mark a web application as distributable, if it supported by your application server."

Can someone provide a little more info/context? If possible, I don't need a full background on how the mechanism works (I'm studying for the Web Components exam), just enough to understand in the context of sessions.

Thanks!

Answer 1

Here are some useful lines,

If an application is run in a cluster without being marked as distributable, session changes will only occur on a single JVM. Therefore, when the user connects to one of the other JVM's, their session will not be recognised, and a new session will be created. This may force them to log in again, establishing a 2nd session on the other JVM. As they switch between the two servers, various other problems may arise.