subject.getPrincipals().add(new SimplePrincipal("system"));
    subject.getPrincipals().add(new SimplePrincipal("access-check-user"));
    subject.getPrincipals().add(new SimplePrincipal("user"));

    subject.getPrincipals().add(new SimplePrincipal(username));

public class RestCredentialVerifier implements ICustomCredentialVerifier {
  private static final Logger LOG = LoggerFactory.getLogger(RestCredentialVerifier.class);

  Map<String, String> mapResult = new HashMap<>();

  @Override
  public int verify(String username, char[] passwordPlainText) throws IOException {

    Subject subject = new Subject();
    // Any ONE OF THESE WORK!
    // subject.getPrincipals().add(new SimplePrincipal("system"));
    // subject.getPrincipals().add(new SimplePrincipal("access-check-user"));
    // subject.getPrincipals().add(new SimplePrincipal("user"));

   // This DOES NOT WORK PROPERLY!
    subject.getPrincipals().add(new SimplePrincipal(username));

    subject.setReadOnly();

    RunContext runContext =
        RunContexts.copyCurrent(true).withSubject(subject);

    // Send the authentication details to the database for verification
    int result = runContext.call(new Callable<Integer>() {
      @Override
      public Integer call() throws Exception {

        Map<String, String> mapResult = BEANS.get(IRestAuthenticationService.class)
            .verify(lowerCaseUsername(username), createHashedPassword(passwordPlainText).toString());
        boolean IsAuthenticatedUser =
            mapResult.get("message").equals(TEXTS.get("YouAreNowConnectedToTheServer").trim());
        return IsAuthenticatedUser ? AUTH_OK : AUTH_FAILED;
      }
    });

    return result;
  }


}