Fix cherry-pick issue of using JDK10 API
diff --git a/pulsar-broker/src/test/java/org/apache/pulsar/broker/stats/ConsumerStatsTest.java b/pulsar-broker/src/test/java/org/apache/pulsar/broker/stats/ConsumerStatsTest.java
index e064e56..412efe6 100644
--- a/pulsar-broker/src/test/java/org/apache/pulsar/broker/stats/ConsumerStatsTest.java
+++ b/pulsar-broker/src/test/java/org/apache/pulsar/broker/stats/ConsumerStatsTest.java
@@ -282,7 +282,7 @@
 
         ByteArrayOutputStream output = new ByteArrayOutputStream();
         PrometheusMetricsGenerator.generate(pulsar, exposeTopicLevelMetrics, true, true, output);
-        String metricStr = output.toString(StandardCharsets.UTF_8);
+        String metricStr = output.toString(StandardCharsets.UTF_8.name());
 
         Multimap<String, PrometheusMetricsTest.Metric> metricsMap = PrometheusMetricsTest.parseMetrics(metricStr);
         Collection<PrometheusMetricsTest.Metric> metrics = metricsMap.get("pulsar_consumer_msg_ack_rate");