Fix DefaultCharset warnings

When all error prone warnings are enabled a number of DefaultCharset bug
patterns is reported: [1].

[1] https://errorprone.info/bugpattern/DefaultCharset

Change-Id: I34ce395eacf779e60708b19f127b77284a6e7c5b

src/main/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/AbstractKafkaSubcriber.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/AbstractKafkaSubcriber.java b/src/main/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/AbstractKafkaSubcriber.java
index 25200ad..911471f 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/AbstractKafkaSubcriber.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/AbstractKafkaSubcriber.java
@@ -14,6 +14,8 @@
 
 package com.googlesource.gerrit.plugins.multisite.kafka.consumer;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
+
 import com.google.common.flogger.FluentLogger;
 import com.google.gerrit.extensions.registration.DynamicSet;
 import com.google.gerrit.server.permissions.PermissionBackendException;
@@ -133,7 +135,7 @@
       }
     } catch (Exception e) {
       logger.atSevere().withCause(e).log(
-          "Malformed event '%s': [Exception: %s]", new String(consumerRecord.value()));
+          "Malformed event '%s': [Exception: %s]", new String(consumerRecord.value(), UTF_8));
     }
   }
 

src/test/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/KafkaEventDeserializerTest.java

diff --git a/src/test/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/KafkaEventDeserializerTest.java b/src/test/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/KafkaEventDeserializerTest.java
index ce958cf..2da0c64 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/KafkaEventDeserializerTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/multisite/kafka/consumer/KafkaEventDeserializerTest.java
@@ -15,6 +15,7 @@
 package com.googlesource.gerrit.plugins.multisite.kafka.consumer;
 
 import static com.google.common.truth.Truth.assertThat;
+import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.gson.Gson;
 import com.googlesource.gerrit.plugins.multisite.broker.GsonProvider;
@@ -44,7 +45,8 @@
                 + "\"body\": {}"
                 + "}",
             eventId, eventType, sourceInstanceId, eventCreatedOn);
-    final SourceAwareEventWrapper event = deserializer.deserialize("ignored", eventJson.getBytes());
+    final SourceAwareEventWrapper event =
+        deserializer.deserialize("ignored", eventJson.getBytes(UTF_8));
 
     assertThat(event.getBody().entrySet()).isEmpty();
     assertThat(event.getHeader().getEventId()).isEqualTo(eventId);
@@ -55,11 +57,11 @@
 
   @Test(expected = RuntimeException.class)
   public void kafkaEventDeserializerShouldFailForInvalidJson() {
-    deserializer.deserialize("ignored", "this is not a JSON string".getBytes());
+    deserializer.deserialize("ignored", "this is not a JSON string".getBytes(UTF_8));
   }
 
   @Test(expected = RuntimeException.class)
   public void kafkaEventDeserializerShouldFailForInvalidObjectButValidJSON() {
-    deserializer.deserialize("ignored", "{}".getBytes());
+    deserializer.deserialize("ignored", "{}".getBytes(UTF_8));
   }
 }