Spring Security UserDetails and username -

in current implementation have user entity implements org.springframework.security.core.userdetails.userdetails interface.

    @entity     @table(name = "users")     public class user extends baseentity implements userdetails {          private static final long serialversionuid = 8884184875433252086l;          @id         @generatedvalue(strategy = generationtype.auto)         private integer id;          private string username;          private string password;     .... 

during oauth2 authorization manually create new user object, populate fields , store in database.

according userdetails contract - userdetails.getusername() method can't return null have no values retrieved social networks can used username.

what value in case should returned in user.getusername() method ?

is okay return ?

@override public string getusername() {     return string.valueof(id); } 

if need save entity before have valid value name think that's problem design. having said user.getusername() used display purposes, doubt matters actual value is, long can matched in authentication.