### Question:
HelidonCounter extends MetricImpl implements Counter { @Override public void jsonData(JsonObjectBuilder builder, MetricID metricID) { builder.add(jsonFullKey(metricID), getCount()); } private  HelidonCounter(String registryType, Metadata metadata, Counter delegate); @Override void inc(); @Override void inc(long n); @Override long getCount(); @Override String prometheusNameWithUnits(MetricID metricID); @Override String prometheusValue(); @Override void jsonData(JsonObjectBuilder builder, MetricID metricID); @Override boolean equals(Object o); @Override int hashCode(); @Override String toString();  }### Answer:
@Test void testJsonData() { counter.inc(47); wrappingCounter.inc(47); JsonObject expected = Json.createReader(new StringReader("{\"theName;a=b;c=d\": 47}")).readObject(); JsonObjectBuilder builder = Json.createObjectBuilder(); counter.jsonData(builder, counterID); assertThat(builder.build(), is(expected)); expected = Json.createReader(new StringReader("{\"theName\": 49}")).readObject(); builder = Json.createObjectBuilder(); wrappingCounter.jsonData(builder, wrappingCounterID); assertThat(builder.build(), is(expected)); }