[FLINK-36822][build] Enable spotless for java 21

flink-clients/src/main/java/org/apache/flink/client/program/rest/RestClusterClientConfiguration.java

@@ -57,17 +57,23 @@ public RestClientConfiguration getRestClientConfiguration() {
         return restClientConfiguration;
     }
 
-    /** @see RestOptions#AWAIT_LEADER_TIMEOUT */
+    /**
+     * @see RestOptions#AWAIT_LEADER_TIMEOUT
+     */
     public long getAwaitLeaderTimeout() {
         return awaitLeaderTimeout;
     }
 
-    /** @see RestOptions#RETRY_MAX_ATTEMPTS */
+    /**
+     * @see RestOptions#RETRY_MAX_ATTEMPTS
+     */
     public int getRetryMaxAttempts() {
         return retryMaxAttempts;
     }
 
-    /** @see RestOptions#RETRY_DELAY */
+    /**
+     * @see RestOptions#RETRY_DELAY
+     */
     public long getRetryDelay() {
         return retryDelay;
     }

flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/reader/fetcher/SplitFetcher.java

@@ -54,6 +54,7 @@ public class SplitFetcher<E, SplitT extends SourceSplit> implements Runnable {
 
     @GuardedBy("lock")
     private final Deque<SplitFetcherTask> taskQueue = new ArrayDeque<>();
+
     // track the assigned splits so we can suspend the reader when there is no splits assigned.
     private final Map<String, SplitT> assignedSplits = new HashMap<>();
     private final FutureCompletingBlockingQueue<RecordsWithSplitIds<E>> elementsQueue;

flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/source/reader/splitreader/SplitsChange.java

@@ -32,7 +32,9 @@ public abstract class SplitsChange<SplitT> {
         this.splits = splits;
     }
 
-    /** @return the list of splits. */
+    /**
+     * @return the list of splits.
+     */
     public List<SplitT> splits() {
         return Collections.unmodifiableList(splits);
     }

flink-connectors/flink-connector-base/src/main/java/org/apache/flink/connector/base/table/options/TableOptionsUtils.java

@@ -34,6 +34,8 @@ public interface TableOptionsUtils {
      */
     Map<String, String> getProcessedResolvedOptions();
 
-    /** @return Common prefix of the options handled by this options handler. */
+    /**
+     * @return Common prefix of the options handled by this options handler.
+     */
     List<String> getNonValidatedPrefixes();
 }

flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/sink/compactor/RecordWiseFileCompactor.java

@@ -65,7 +65,9 @@ public interface Writer<T> {
      */
     public interface Reader<T> extends AutoCloseable {
 
-        /** @return The next record, or null if no more available. */
+        /**
+         * @return The next record, or null if no more available.
+         */
         T read() throws IOException;
 
         /**

flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/table/stream/PartitionTimeCommitPredicate.java

@@ -45,6 +45,7 @@ public class PartitionTimeCommitPredicate implements PartitionCommitPredicate {
     private final PartitionTimeExtractor extractor;
     private final long commitDelay;
     private final List<String> partitionKeys;
+
     /** The time zone used to parse the long watermark value to TIMESTAMP. */
     private final ZoneId watermarkTimeZone;
 

flink-connectors/flink-connector-files/src/main/java/org/apache/flink/connector/file/table/stream/TaskTracker.java

@@ -40,7 +40,9 @@ public TaskTracker(int numberOfTasks) {
         this.numberOfTasks = numberOfTasks;
     }
 
-    /** @return true, if this checkpoint id need be committed. */
+    /**
+     * @return true, if this checkpoint id need be committed.
+     */
     public boolean add(long checkpointId, int task) {
         Set<Integer> tasks = notifiedTasks.computeIfAbsent(checkpointId, (k) -> new HashSet<>());
         tasks.add(task);

flink-connectors/flink-connector-files/src/test/java/org/apache/flink/connector/file/src/testutils/TestingFileSystem.java

@@ -253,6 +253,7 @@ public boolean rename(Path src, Path dst) throws IOException {
     public boolean isDistributedFS() {
         return false;
     }
+
     // ------------------------------------------------------------------------
 
     /** Test implementation of a {@link FileStatus}. */

flink-connectors/flink-file-sink-common/src/main/java/org/apache/flink/streaming/api/functions/sink/filesystem/BucketWriter.java

@@ -81,7 +81,9 @@ InProgressFileWriter<IN, BucketID> resumeInProgressFileFrom(
             final long creationTime)
             throws IOException;
 
-    /** @return the property of the {@link BucketWriter} */
+    /**
+     * @return the property of the {@link BucketWriter}
+     */
     WriterProperties getProperties();
 
     /**

flink-connectors/flink-file-sink-common/src/main/java/org/apache/flink/streaming/api/functions/sink/filesystem/InProgressFileWriter.java

@@ -68,11 +68,15 @@ interface InProgressFileRecoverable extends PendingFileRecoverable {}
     /** The handle can be used to recover pending file. */
     interface PendingFileRecoverable {
 
-        /** @return The target path of the pending file, null if unavailable. */
+        /**
+         * @return The target path of the pending file, null if unavailable.
+         */
         @Nullable
         Path getPath();
 
-        /** @return The size of the pending file, -1 if unavailable. */
+        /**
+         * @return The size of the pending file, -1 if unavailable.
+         */
         long getSize();
     }
 }

flink-connectors/flink-file-sink-common/src/main/java/org/apache/flink/streaming/api/functions/sink/filesystem/PartFileInfo.java

@@ -35,12 +35,18 @@ public interface PartFileInfo<BucketID> {
      */
     BucketID getBucketId();
 
-    /** @return The creation time (in ms) of the currently open part file. */
+    /**
+     * @return The creation time (in ms) of the currently open part file.
+     */
     long getCreationTime();
 
-    /** @return The size of the currently open part file. */
+    /**
+     * @return The size of the currently open part file.
+     */
     long getSize() throws IOException;
 
-    /** @return The last time (in ms) the currently open part file was written to. */
+    /**
+     * @return The last time (in ms) the currently open part file was written to.
+     */
     long getLastUpdateTime();
 }

flink-connectors/flink-file-sink-common/src/main/java/org/apache/flink/streaming/api/functions/sink/filesystem/WriterProperties.java

@@ -55,13 +55,17 @@ public boolean supportsResume() {
         return supportsResume;
     }
 
-    /** @return the serializer for the {@link InProgressFileWriter.PendingFileRecoverable}. */
+    /**
+     * @return the serializer for the {@link InProgressFileWriter.PendingFileRecoverable}.
+     */
     public SimpleVersionedSerializer<InProgressFileWriter.PendingFileRecoverable>
             getPendingFileRecoverableSerializer() {
         return pendingFileRecoverableSerializer;
     }
 
-    /** @return the serializer for the {@link InProgressFileWriter.InProgressFileRecoverable}. */
+    /**
+     * @return the serializer for the {@link InProgressFileWriter.InProgressFileRecoverable}.
+     */
     public SimpleVersionedSerializer<InProgressFileWriter.InProgressFileRecoverable>
             getInProgressFileRecoverableSerializer() {
         return inProgressFileRecoverableSerializer;

flink-connectors/flink-hadoop-compatibility/src/main/java/org/apache/flink/api/java/typeutils/runtime/WritableSerializer.java

@@ -135,6 +135,7 @@ private void checkKryoInitialized() {
             this.kryo.register(typeClass);
         }
     }
+
     // --------------------------------------------------------------------------------------------
 
     @Override

flink-core-api/src/main/java/org/apache/flink/api/java/tuple/Tuple.java

@@ -208,6 +208,7 @@ public static Tuple newInstance(int arity) {
                 Tuple24.class,
                 Tuple25.class
             };
+
     // END_OF_TUPLE_DEPENDENT_CODE
 
     /**

flink-core-api/src/main/java/org/apache/flink/api/java/tuple/Tuple10.java

@@ -62,22 +62,31 @@ public class Tuple10<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9> extends Tuple {
 
     /** Field 0 of the tuple. */
     public T0 f0;
+
     /** Field 1 of the tuple. */
     public T1 f1;
+
     /** Field 2 of the tuple. */
     public T2 f2;
+
     /** Field 3 of the tuple. */
     public T3 f3;
+
     /** Field 4 of the tuple. */
     public T4 f4;
+
     /** Field 5 of the tuple. */
     public T5 f5;
+
     /** Field 6 of the tuple. */
     public T6 f6;
+
     /** Field 7 of the tuple. */
     public T7 f7;
+
     /** Field 8 of the tuple. */
     public T8 f8;
+
     /** Field 9 of the tuple. */
     public T9 f9;
 

flink-core-api/src/main/java/org/apache/flink/api/java/tuple/Tuple11.java

@@ -63,24 +63,34 @@ public class Tuple11<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10> extends Tuple
 
     /** Field 0 of the tuple. */
     public T0 f0;
+
     /** Field 1 of the tuple. */
     public T1 f1;
+
     /** Field 2 of the tuple. */
     public T2 f2;
+
     /** Field 3 of the tuple. */
     public T3 f3;
+
     /** Field 4 of the tuple. */
     public T4 f4;
+
     /** Field 5 of the tuple. */
     public T5 f5;
+
     /** Field 6 of the tuple. */
     public T6 f6;
+
     /** Field 7 of the tuple. */
     public T7 f7;
+
     /** Field 8 of the tuple. */
     public T8 f8;
+
     /** Field 9 of the tuple. */
     public T9 f9;
+
     /** Field 10 of the tuple. */
     public T10 f10;
 

flink-core-api/src/main/java/org/apache/flink/api/java/tuple/Tuple12.java

@@ -64,26 +64,37 @@ public class Tuple12<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11> extends T
 
     /** Field 0 of the tuple. */
     public T0 f0;
+
     /** Field 1 of the tuple. */
     public T1 f1;
+
     /** Field 2 of the tuple. */
     public T2 f2;
+
     /** Field 3 of the tuple. */
     public T3 f3;
+
     /** Field 4 of the tuple. */
     public T4 f4;
+
     /** Field 5 of the tuple. */
     public T5 f5;
+
     /** Field 6 of the tuple. */
     public T6 f6;
+
     /** Field 7 of the tuple. */
     public T7 f7;
+
     /** Field 8 of the tuple. */
     public T8 f8;
+
     /** Field 9 of the tuple. */
     public T9 f9;
+
     /** Field 10 of the tuple. */
     public T10 f10;
+
     /** Field 11 of the tuple. */
     public T11 f11;
 

flink-core-api/src/main/java/org/apache/flink/api/java/tuple/Tuple13.java

@@ -65,28 +65,40 @@ public class Tuple13<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12> exte
 
     /** Field 0 of the tuple. */
     public T0 f0;
+
     /** Field 1 of the tuple. */
     public T1 f1;
+
     /** Field 2 of the tuple. */
     public T2 f2;
+
     /** Field 3 of the tuple. */
     public T3 f3;
+
     /** Field 4 of the tuple. */
     public T4 f4;
+
     /** Field 5 of the tuple. */
     public T5 f5;
+
     /** Field 6 of the tuple. */
     public T6 f6;
+
     /** Field 7 of the tuple. */
     public T7 f7;
+
     /** Field 8 of the tuple. */
     public T8 f8;
+
     /** Field 9 of the tuple. */
     public T9 f9;
+
     /** Field 10 of the tuple. */
     public T10 f10;
+
     /** Field 11 of the tuple. */
     public T11 f11;
+
     /** Field 12 of the tuple. */
     public T12 f12;
 

flink-core-api/src/main/java/org/apache/flink/api/java/tuple/Tuple14.java

@@ -66,30 +66,43 @@ public class Tuple14<T0, T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13>
 
     /** Field 0 of the tuple. */
     public T0 f0;
+
     /** Field 1 of the tuple. */
     public T1 f1;
+
     /** Field 2 of the tuple. */
     public T2 f2;
+
     /** Field 3 of the tuple. */
     public T3 f3;
+
     /** Field 4 of the tuple. */
     public T4 f4;
+
     /** Field 5 of the tuple. */
     public T5 f5;
+
     /** Field 6 of the tuple. */
     public T6 f6;
+
     /** Field 7 of the tuple. */
     public T7 f7;
+
     /** Field 8 of the tuple. */
     public T8 f8;
+
     /** Field 9 of the tuple. */
     public T9 f9;
+
     /** Field 10 of the tuple. */
     public T10 f10;
+
     /** Field 11 of the tuple. */
     public T11 f11;
+
     /** Field 12 of the tuple. */
     public T12 f12;
+
     /** Field 13 of the tuple. */
     public T13 f13;