How about the following method? The 2nd parameter is driven from storm_conf. We add it here to make plugin development easier, and ensure all plugins use "java.security.auth.login.config" in storm configuration.  

    /**
     * Invoked once immediately after construction
     * @param storm_conf Storm configuration 
     * @param login_conf login configuration
     */
    void prepare(Map storm_conf, javax.security.auth.login.Configuration login_conf);