Jetty client Error StatisticsHandler has no Wrapped Handler

[falconwin]

I am following the Prometheus Java client library to expose metrics of my Jetty server. From [here]

But when I start the server I get the error -

Exception in thread "main" java.lang.RuntimeException: Unable to start jetty server
Caused by: java.lang.IllegalStateException: StatisticsHandler has no Wrapped Handler

To fix this I had to do -

    StatisticsHandler stats = new StatisticsHandler();
    stats.setServer(server.getServer());
    HandlerWrapper hw = new HandlerWrapper();
    stats.setHandler(hw);
    new JettyStatisticsCollector(stats).register();

    contextCollectionHandler.addHandler(stats);
    server.setHandler(contextCollectionHandler);

    try {
        server.start();
    }
    catch (final Exception e) {
        throw new RuntimeException("Unable to start jetty server", e);
    }

But, I dont see the stats incrementing, when I make requests to my server through Postman. I get responses, 200, 404 etc. But none of the stats such as jetty_requests_total or jetty_responses_total are incrementing. They stay at 0. The only thing that changes is jetty_stats_seconds. What am I doing wrong ?