feat: version bump kafka-clients to 3.1.0 and clean up assorted warnings

pom.xml

@@ -27,7 +27,7 @@
     <dependency>
       <groupId>org.apache.kafka</groupId>
       <artifactId>kafka-clients</artifactId>
-      <version>2.8.1</version>
+      <version>3.1.0</version>
     </dependency>
     <dependency>
       <groupId>com.google.api</groupId>

src/main/java/com/google/cloud/pubsublite/kafka/ConsumerSettings.java

@@ -68,7 +68,7 @@ public abstract class ConsumerSettings {
   abstract Optional<TopicPath> topicPathOverride();
 
   public static Builder newBuilder() {
-    return (new AutoValue_ConsumerSettings.Builder()).setAutocommit(false);
+    return new AutoValue_ConsumerSettings.Builder().setAutocommit(false);
   }
 
   @AutoValue.Builder

src/main/java/com/google/cloud/pubsublite/kafka/KafkaExceptionUtils.java

@@ -63,8 +63,9 @@ static KafkaException toKafkaException(CheckedApiException source) {
         return new KafkaException("Unimplemented.", source);
       case UNKNOWN:
         return new KafkaException("Unknown.", source);
+      default:
+        return new KafkaException("No case.", source);
     }
-    return new KafkaException("No case.", source);
   }
 
   /**

src/main/java/com/google/cloud/pubsublite/kafka/LiteHeaders.java

@@ -21,9 +21,7 @@
 import com.google.common.collect.Iterables;
 import com.google.common.collect.Iterators;
 import com.google.protobuf.ByteString;
-import java.util.Collection;
 import java.util.Iterator;
-import java.util.List;
 import org.apache.kafka.common.header.Header;
 import org.apache.kafka.common.header.Headers;
 
@@ -48,12 +46,6 @@ public byte[] value() {
     };
   }
 
-  private static List<Header> toHeaders(String key, Collection<ByteString> values) {
-    ImmutableList.Builder<Header> headersBuilder = ImmutableList.builder();
-    values.forEach(value -> headersBuilder.add(toHeader(key, value)));
-    return headersBuilder.build();
-  }
-
   @Override
   public Headers add(Header header) throws IllegalStateException {
     throw new IllegalStateException();

src/main/java/com/google/cloud/pubsublite/kafka/PubsubLiteConsumer.java

@@ -47,6 +47,7 @@
 import java.util.List;
 import java.util.Map;
 import java.util.Optional;
+import java.util.OptionalLong;
 import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
@@ -250,10 +251,6 @@ public void unsubscribe() {
     consumer = Optional.empty();
   }
 
-  private static Duration toDuration(long l, TimeUnit timeUnit) {
-    return Duration.ofMillis(TimeUnit.MILLISECONDS.convert(l, timeUnit));
-  }
-
   @Override
   public ConsumerRecords<byte[], byte[]> poll(long l) {
     return poll(Duration.ofMillis(l));
@@ -433,11 +430,10 @@ public Map<TopicPartition, OffsetAndMetadata> committed(
               .get(timeout.toMillis(), TimeUnit.MILLISECONDS);
       ImmutableMap.Builder<TopicPartition, OffsetAndMetadata> output = ImmutableMap.builder();
       targets.forEach(
-          partition -> {
-            output.put(
-                toTopicPartition(partition),
-                new OffsetAndMetadata(full_map.getOrDefault(partition, Offset.of(0)).value()));
-          });
+          partition ->
+              output.put(
+                  toTopicPartition(partition),
+                  new OffsetAndMetadata(full_map.getOrDefault(partition, Offset.of(0)).value())));
       return output.build();
     } catch (Throwable t) {
       throw toKafka(t);
@@ -483,7 +479,7 @@ public Map<TopicPartition, OffsetAndTimestamp> offsetsForTimes(
           map.entrySet().stream()
               .collect(
                   Collectors.toMap(
-                      entry -> entry.getKey(),
+                      Map.Entry::getKey,
                       entry ->
                           topicStatsClient.computeCursorForEventTime(
                               topicPath,
@@ -561,11 +557,6 @@ public void close() {
     close(INFINITE_DURATION);
   }
 
-  @Override
-  public void close(long l, TimeUnit timeUnit) {
-    close(toDuration(l, timeUnit));
-  }
-
   @Override
   public void close(Duration timeout) {
     unsubscribe();
@@ -606,6 +597,12 @@ public void enforceRebalance() {
     logger.atWarning().log("Calling enforceRebalance on a Pub/Sub Lite Consumer is a no-op.");
   }
 
+  @Override
+  public OptionalLong currentLag(TopicPartition topicPartition) {
+    logger.atWarning().log("Calling currentLag on a Pub/Sub Lite Consumer always returns empty.");
+    return OptionalLong.empty();
+  }
+
   @Override
   public void wakeup() {
     requireValidConsumer().wakeup();

src/test/java/com/google/cloud/pubsublite/kafka/PubsubLiteConsumerTest.java

@@ -103,7 +103,7 @@ private static <T> T example(Class<T> klass) {
             .put(TopicPartition.class, exampleTopicPartition())
             .put(OffsetAndMetadata.class, exampleOffsetAndMetadata())
             .build();
-    T instance = (T) map.getInstance(klass);
+    T instance = map.getInstance(klass);
     if (instance != null) return instance;
     return UnitTestExamples.example(klass);
   }