public void setSessionId(Serializable sessionId) {
        this.sessionId = sessionId;
    }
Default implementation of the {@link SessionKey} interface, which allows setting and retrieval of a concrete
{@link #getSessionId() sessionId} that the {@code SessionManager} implementation can use to look up a
{@code Session} instance.

@since 1.0
core/src/main/java/org/apache/shiro/session/mgt/DefaultSessionKey.java