fix checkstyle and SuppressFBWarnings

Author: LiuGuH

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/DataNode.java

@@ -264,6 +264,8 @@
 import org.apache.hadoop.util.DiskChecker.DiskErrorException;
 import org.apache.hadoop.util.concurrent.HadoopExecutors;
 import org.apache.hadoop.tracing.Tracer;
+
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
 import org.eclipse.jetty.util.ajax.JSON;
 
 import org.apache.hadoop.classification.VisibleForTesting;
@@ -2835,6 +2837,7 @@ private void reportBadBlock(final BPOfferService bpos,
     LOG.warn(msg);
   }
 
+  @SuppressFBWarnings()
   @VisibleForTesting
   void transferBlock(ExtendedBlock block, DatanodeInfo[] xferTargets,
       StorageType[] xferTargetStorageTypes, String[] xferTargetStorageIDs)

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/BlockPoolSlice.java

@@ -139,7 +139,7 @@ public int compare(File f1, File f2) {
   private volatile GetSpaceUsed dfsUsage;
 
   /**
-   * Create a blook pool slice
+   * Create a blook pool slice.
    * @param bpid Block pool Id
    * @param volume {@link FsVolumeImpl} to which this BlockPool belongs to
    * @param bpDir directory corresponding to the BlockPool

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/FsDatasetImpl.java

@@ -68,7 +68,6 @@
 import org.apache.hadoop.hdfs.server.datanode.FileIoProvider;
 import org.apache.hadoop.hdfs.server.datanode.FinalizedReplica;
 import org.apache.hadoop.hdfs.server.datanode.LocalReplica;
-import org.apache.hadoop.hdfs.server.datanode.LocalReplicaInPipeline;
 import org.apache.hadoop.hdfs.server.datanode.metrics.DataNodeMetrics;
 import org.apache.hadoop.util.AutoCloseableLock;
 import org.apache.hadoop.hdfs.protocol.Block;
@@ -3875,7 +3874,7 @@ public void hardLinkOneBlock(ExtendedBlock srcBlock, ExtendedBlock dstBlock) thr
         DatanodeUtil.getMetaName(dstBlock.getBlockName(), dstBlock.getGenerationStamp()));
     File dstBlockFile = new File(dstTmpDir, dstBlock.getBlockName());
 
-    File files[] = hardLinkBlockFiles(srcReplicaInfo, dstMeta, dstBlockFile);
+    File[] files = hardLinkBlockFiles(srcReplicaInfo, dstMeta, dstBlockFile);
 
     ReplicaInfo dstReplicaInfo = new ReplicaBuilder(ReplicaState.TEMPORARY)
         .setBlockId(dstBlock.getBlockId())