Singleton across JVM or Application instance or Tomcat instance

Question

If I deploy and run 2 instances of same application on a single instance of Tomcat(Or any other server). Then a single object(of a Singleton class) would be created:

Answer 1

As far as I know, a singleton is unique per classloader. So I think the answer to your question depends on the way the container loads the web application.

If it allocates one classloader per web app, then it seems like you would get two, completely independent, singleton objects. If it allocates one classloader and all web apps use it, then they share the same singlet one instance.