code: public Request<Client> get(String clientId) {
          Asserts.assertNotNull(clientId, "client id");
  
          String url = baseUrl
                  .newBuilder()
                  .addPathSegments("api/v2/clients")
                  .addPathSegment(clientId)
                  .build()
                  .toString();
          CustomRequest<Client> request = new CustomRequest<>(client, url, "GET", new TypeReference<Client>() {
          });
          request.addHeader("Authorization", "Bearer " + apiToken);
          return request;
      }
docs: Request an Application. A token with scope read:clients is needed. If you also need the client_secret and encryption_key attributes the token must have read:client_keys scope.
  See https://auth0.com/docs/api/management/v2#!/Clients/get_clients_by_id
  
  @param clientId the application's client id.
  @return a Request to execute.