code: private static void validateCredentials() {
          try {
              Account.get().getAccountInfo();
          } catch (Exception e) {
              if (e instanceof AppPlatformException) {
                  AppPlatformException appEx = (AppPlatformException) e;
  
                  if (appEx.getStatus() == 401){
                      throw new InvalidCredentialsException();
                  }
              } else {
                  throw new RuntimeException(e);
              }
          }
      }
docs: Validate if the credentials are set and has access to catapult