java version "1.5.0_05"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_05-b05)
Java HotSpot(TM) Client VM (build 1.5.0_05-b05, mixed mode, sharing)
Since you use the term request...
If you're in a Servlet environment things are different again.
The Servlet itself is always multithreaded per request, so every object
you instantiate might very well be overwritten by the other thread
from the other request - if you place its declaration in a servlet scope.
Please explain a bit how your environment looks.