Please respond to my Query
Is there a way to set the principal of the callBackHandler explicitly
Your request is hard to understand, but I think what you are asking for is to have the JAAS layer set a new user principal (different from the username principal) obtained from realm to replace the username principal. If this is correct, then I think that is why JBoss has the 'CallerPrinicpal' Subject usage pattern. So I think you may need to extend the LDAP login module to handle this in a custom fashion.
Does this solve your problem? cgriffith