fix checkstyle

Author: hfutatzhanghb

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

@@ -133,7 +133,8 @@ public static File idToBlockDir(File root, long blockId) {
    * Take an example. We hava a block with blockid mapping to:
    * "/data1/hadoop/hdfs/datanode/current/BP-xxxx/current/finalized/subdir0/subdir0"
    * We return "subdir0/subdir0"
-   * @return
+   * @param blockId blockId
+   * @return The two-level subdir name
    */
   public static String idToBlockDirSuffixName(long blockId) {
     int d1 = (int) ((blockId >> 16) & 0x1F);

hadoop-hdfs-project/hadoop-hdfs/src/test/java/org/apache/hadoop/hdfs/server/datanode/fsdataset/impl/TestFsDatasetImpl.java

@@ -68,7 +68,6 @@
 import org.apache.hadoop.hdfs.server.datanode.FinalizedReplica;
 import org.apache.hadoop.hdfs.server.datanode.ReplicaHandler;
 import org.apache.hadoop.hdfs.server.datanode.ReplicaInfo;
-import org.apache.hadoop.hdfs.server.datanode.ReplicaNotFoundException;
 import org.apache.hadoop.hdfs.server.datanode.ShortCircuitRegistry;
 import org.apache.hadoop.hdfs.server.datanode.StorageLocation;
 import org.apache.hadoop.hdfs.server.datanode.fsdataset.DataNodeVolumeMetrics;