code: @GET
      @Produces(MediaType.APPLICATION_JSON)
      @Path("/userinfo")
      @Description("Returns the user info of the user who is logged in.")
      public PrincipalUserDto userInfo(@Context HttpServletRequest req) {
          String userName=findUserByToken(req);
          PrincipalUser user = _uService.findUserByUsername(userName);
          return PrincipalUserDto.transformToDto(user);
      }
docs: OAuth2.0 UserInfo reference implementation to get logged in user information using the access token
  @param req   The Http Request with authorization header
  @return      User Information Json Object