code: public static void registerHealthChecks(final HikariPool pool, final HikariConfig hikariConfig, final HealthCheckRegistry registry)
     {
        final Properties healthCheckProperties = hikariConfig.getHealthCheckProperties();
        final MetricRegistry metricRegistry = (MetricRegistry) hikariConfig.getMetricRegistry();
  
        final long checkTimeoutMs = Long.parseLong(healthCheckProperties.getProperty("connectivityCheckTimeoutMs", String.valueOf(hikariConfig.getConnectionTimeout())));
        registry.register(MetricRegistry.name(hikariConfig.getPoolName(), "pool", "ConnectivityCheck"), new ConnectivityHealthCheck(pool, checkTimeoutMs));
  
        final long expected99thPercentile = Long.parseLong(healthCheckProperties.getProperty("expected99thPercentileMs", "0"));
        if (metricRegistry != null && expected99thPercentile > 0) {
           SortedMap<String,Timer> timers = metricRegistry.getTimers((name, metric) -> name.equals(MetricRegistry.name(hikariConfig.getPoolName(), "pool", "Wait")));
  
           if (!timers.isEmpty()) {
              final Timer timer = timers.entrySet().iterator().next().getValue();
              registry.register(MetricRegistry.name(hikariConfig.getPoolName(), "pool", "Connection99Percent"), new Connection99Percent(timer, expected99thPercentile));
           }
        }
     }
docs: Register Dropwizard health checks.
  
  @param pool the pool to register health checks for
  @param hikariConfig the pool configuration
  @param registry the HealthCheckRegistry into which checks will be registered