if (username != null && SecurityContextHolder.getContext().getAuthentication() == null) {
      UserDetails userDetails = User.withUsername(username).password("").build();

      UsernamePasswordAuthenticationToken authenticationToken = new UsernamePasswordAuthenticationToken(
        userDetails, null);
      authenticationToken.setDetails(new WebAuthenticationDetailsSource().buildDetails(request));
      SecurityContextHolder.getContext().setAuthentication(authenticationToken);

    }