Here are two sol:
In the action class, using the request object (like in
servlets), you can get the session object and can store the object in session.
If all the attributes in person belong to a separate form, then the form bean can be stored in scope by specifying in action mappings (default is session).
I don't think scope can be specified more than the application context.
Hope this may help you.
Can you elaborate on your question - Specifically, can another web application access struts session and dump an object in there?