A {@code SessionKey} is a key that allows look-up of any particular {@link hunt.shiro.session.Session Session} instance. This is not to be confused what is probably better recognized as a session <em>attribute</em> key - a key that is used to acquire a session attribute via the {@link hunt.shiro.session.Session#getAttribute(Object) Session.getAttribute} method. A {@code SessionKey} looks up a Session object directly. <p/> While a {@code SessionKey} allows lookup of <em>any</em> Session that might exist, this is not something in practice done too often by most Shiro end-users. Instead, it is usually more convenient to acquire the currently executing {@code Subject}'s session via the {@link hunt.shiro.subject.Subject#getSession} method. This interface and its usages are best suited for framework development.