It use "software" word, thus is it speak about software architecture?
But sometimes it seems to speak about hardware, for example
What is yours thought?
If I have a classical j2ee application with jsp/servlets (presentation tier) and EJBs (business tier) and I deploy web container and EJB container in the same single app server in the same single physical server, is this 2 tier or 3 tier?
And if I have the RDBMS in the same single physical server too, this is 3, 2 or 1 tier?
I think it is somewhat of both. In your case, you chose to deploy it on server - but your architecture allows it to be deployed to several servers: the web components could go to web server, and EJB components could live on a application server. Usually, in J2EE application, you would also access database, which can live in its own server box, right? So, in classical J2EE architecture you have 3 tiers, even when you choose to collapse some of them for the time being.