title: Spring's WebUtils.getSessionMutex(javax.servlet.http.HttpSession) and HttpSessionMutexListener still relevant
body: <p>I'd like to know if the Spring framework's <code>HttpSessionMutexListener</code> listener is still relevant in today's application servers/web containers (say 2.5+ servlet spec servers like Tomcat 6 or Tomcat 7) for locking the session object in clustered environments (ie. among different JVMs), or do they only resolve the concurrency issue in clustered environments for 2.3 (or previous) servlet spec containers and now it is unnecessary?</p>