I have worked on a OAM 11g requirement that needs to do authentication based on only username. There is a OOTB authentication scheme available in OAM 11g called LDAPNoPasswordValidationScheme. This authentication scheme uses the Authentication module LDAPNoPasswordAuthModule and that in turn points to Embedded Weblogic identity store by default.
I have to perform all this authentication using OAM 11g API. So I have created a dummy resource to test this. Pointed the LDAPNoPasswordAuthModule to OVD identity store as we are using OVD.
Used the below code snippet to test this and it worked fine.
ResourceRequest req = new ResourceRequest(“http”, “http://host:port/dummy”,”GET”);
Hashtable credentials = new Hashtable();
session = new UserSession(req,credentials);
The Resource http://host:port/dummy is protected using LDAPNoPasswordValidationScheme and thus session token is created with just username.