How to Set and Get Session values in Zend Framework

//To set the session
Initialize the session name space
$this->nameSpace = new Zend_Session_Namespace('HN');
$this->nameSpace->userId = 'userId';

//To get the session value
Initialize the session name space
$this->nameSpace = new Zend_Session_Namespace('HN');
$userId = $this->nameSpace->userId;