servlet running in different JVM than other servlets

[Josh Johnson]

In a web application I am working on, I have a servlet that can't seem to communicate with other servlets and JSP pages. There are 3 strange things happening.
1) If this servlet stores something in the Session, other servlets don't get that same session when they do a getSession().
2) If this servlet stores an attribute in the servlet context, other servlets can't see that attribute.
3) If this servlet instantiates a Singleton object (that all servlets are meant to share; ex: ConnectionPool), other servlets instantiate a whole new instance when they call getInstance() at a later time.
All the other servlets/JSPs share the ServletContext and Singleton objects. So this servlet looks like it runs in a separate JVM or is considered to be part of a separate web application. I just can't figure out why.
Tomcat is the servlet container we are using.
Any ideas?

[Tim Holloway]

Tomcat has a number of ways of being configured and the number of JVMs can vary according to which you use. However, a "vanilla" tomcat I don't think is creating a distinct JVM for each servlet.
I suspect that a major problem you're having is not being aware of the details of the rules for session domains. A session is created (or retrieved) based on its URL name - check the docs for the exact details.

[ruijin yang]

Did you use:
HttpSession session=req.getSession(false);
?
--------------------
ruijin yang
SCJP2

[Josh Johnson]

It appears that the problem I was having was somehow caused by Tomcat.
I just moved the web app to iPlanet, and this problem does not occur anymore. Now sessions created by the troublesome servlet are seen by other servlets and jsp pages.