public T get() {
                Subject subject = ThreadContext.getSubject();
                if (subject == null) {
                    throw new OutOfScopeException("There is no Shiro Session currently in scope.");
                }
                Session session = subject.getSession();
                T scoped = castSessionAttribute(session);
                if (scoped == null) {
                    scoped = unscoped.get();
                }
                return scoped;
            }
Guice scope for Shiro sessions.  Not bound by default.
support/guice/src/main/java/org/apache/shiro/guice/ShiroSessionScope.java