The User Management Engine (UME) provides central user administration for all Java applications. The UME is completely integrated into SAP Web Application Server Java and is used as the default user store as of SAP Web Application Server 6.40. The UME is integrated into SAP Web Application Server Java as a service. (Quelle: http://www.sapsecurityonline.com/enterprise_portal/web_as_security.htm)