### Question:
DefaultMetricsReader implements MetricsReader { @Override public List<MetricName> readableNames() { return Arrays.asList(readableNames); } DefaultMetricsReader(); @Override List<MetricName> readableNames(); @Override MetricValue readValue(MetricName name);  }### Answer:
@Test public void testGetReadableNames() { System.out.println("testGetReadableNames"); DefaultMetricsReader reader = new DefaultMetricsReader(); List<MetricName> names = reader.readableNames(); assertThat(names, containsInAnyOrder( MetricName.CPU_UTILIZATION, MetricName.HEAP_SIZE, MetricName.HEAP_UTILIZATION, MetricName.OPERATOR_LATENCY, MetricName.QUEUE_LENGTH)); }