Using Basic Authentication (User ID and Password) 

Basic Authentication is an HTTP standard method to use for authentication, whereby the user provides a user ID and password for authentication. Per default, the SAP J2EE Engine uses Basic Authentication for applications that are set up to use basic or form authentication. The corresponding login module is BasicPasswordLoginModule.

You can configure the LogonWithAlias option of the BasicPasswordLoginModule to enable logon with an ABAP alias. The possible values for this option are true or false. The default value for this option is false. If you change this value to true, then entered usernames are regarded as ABAP aliases. 

Users can have an alias only if the User Management Engine uses an ABAP user store. Adding an alias for a user account is possible only from the ABAP backend user store. For more information, see Logon Data Tab Page for user management in the ABAP system.

When using basic authentication, the user’s information is passed to the server over the HTTP connection in a header variable as a base-64 encoded string. When using form-based authentication, the information is passed using the HTTP POST method.