Foolish Java / Tomcat question

[Jon Yeargers]

<asbestos underwear>
 
So I get the concept of the garbage collector.. at least in principal..
but what happens to all the memory that gets allocated for a tomcat
session (by a single login) when that session closes or is timed out? 
 
is *everything* from that session decremented so it can be cleaned up?
 
do I need to be checking for this?
 
what about session beans and variables stored therein?
 
</asbestos underwear>
 
thanks. let the scorching begin.