Grails dropwizard-metrics plugin doesn't output Metrics data in correct format

Question

I was looking for replacement of yammer-metrics plugin for Grails 3.x & found Grails Dropwizard Metrics for the same.

I was trying to integrate it with my sample application(in Grails 3.x) and was following the documentation given at : http://grails-plugins.github.io/grails-dropwizard-metrics/snapshot/index.html#_healthcheck_beans

Following the blog, I have added below dependencies in build.gradle i.e

compile "org.grails.plugins:dropwizard-metrics:1.0.0.BUILD-SNAPSHOT"

And to test this, I made TestController with index() action i.e

import grails.plugin.dropwizard.metrics.timers.Timed

class TestController {

    @Timed('test1')
    def index() {
        render 'ok'
    }
}

With this, running the application and hitting /test/index and then /metrics, No longer returns a valid JSON, containing version, gaugues, counters, timers tag etc. (as seen in http://grails-plugins.github.io/grails-dropwizard-metrics/snapshot/index.html#_exposing_metrics_data)

Instead it just returns JSON in this format:

{
    "mem": 830779,
    "mem.free": 602088,
    "processors": 4,
    "instance.uptime": 14766,
    "uptime": 30991,
    "systemload.average": -1.0,
    "heap.committed": 749056,
    "heap.init": 786432,
    "heap.used": 146967,
    "heap": 749056,
    "nonheap.committed": 84896,
    "nonheap.init": 2496,
    "nonheap.used": 81724,
    "nonheap": 0,
    "threads.peak": 33,
    "threads.daemon": 29,
    "threads.totalStarted": 37,
    "threads": 32,
    "classes": 11057,
    "classes.loaded": 11057,
    "classes.unloaded": 0,
    "gc.ps_scavenge.count": 18,
    "gc.ps_scavenge.time": 490,
    "gc.ps_marksweep.count": 3,
    "gc.ps_marksweep.time": 854,
    "test1.snapshot.stdDev": 0,
    "gauge.response.test.test1": 335.0,
    "gauge.response.assets.bootstrap.js": 76.0,
    "test1.snapshot.98thPercentile": 31,
    "counter.status.200.assets.grails.css": 1,
    "gauge.response.assets.jquery-2.2.0.min.js": 146.0,
    "test1.snapshot.999thPercentile": 31,
    "counter.status.200.test.test1": 1,
    "gauge.response.assets.grails-cupsonly-logo-white.svg": 3.0,
    "test1.fifteenMinuteRate": 0.2,
    "test1.snapshot.min": 31,
    "test1.snapshot.95thPercentile": 31,
    "test1.meanRate": 0.18974713564659287,
    "gauge.response.assets.favicon.ico": 8.0,
    "gauge.response.assets.mobile.css": 129.0,
    "gauge.response.root": 2301.0,
    "counter.status.200.root": 1,
    "counter.status.200.assets.jquery-2.2.0.min.js": 1,
    "counter.status.200.assets.application.css": 1,
    "gauge.response.assets.main.css": 148.0,
    "test1.snapshot.mean": 31,
    "test1.snapshot.99thPercentile": 31,
    "counter.status.200.assets.main.css": 1,
    "gauge.response.assets.application.css": 152.0,
    "counter.status.200.assets.mobile.css": 1,
    "counter.status.200.assets.grails-cupsonly-logo-white.svg": 1,
    "test1.snapshot.median": 31,
    "gauge.response.assets.grails.css": 145.0,
    "counter.status.200.assets.bootstrap.js": 1,
    "test1.count": 1,
    "test1.oneMinuteRate": 0.2,
    "test1.fiveMinuteRate": 0.2,
    "test1.snapshot.max": 31,
    "test1.snapshot.75thPercentile": 31,
    "gauge.response.assets.application.js": 4.0,
    "counter.status.200.assets.favicon.ico": 2,
    "counter.status.200.assets.application.js": 1,
    "gauge.response.assets.bootstrap.css": 249.0,
    "counter.status.200.assets.bootstrap.css": 1,
    "httpsessions.max": -1,
    "httpsessions.active": 0
}

In my sample application, I had tried to register MetricRegistry bean in resources.groovy too like below:

beans = { metricRegistry(MetricRegistry) }

But still the output JSON is same.

Please let me what I am missing. Thanks in advance!