HDFS-9377. Fix findbugs warnings in FSDirSnapshotOp. (Mingliang Liu via Yongjun Zhang)

hadoop-hdfs-project/hadoop-hdfs/CHANGES.txt

@@ -1626,6 +1626,9 @@ Release 2.8.0 - UNRELEASED
     HDFS-9363. Add fetchReplica() to FsDatasetTestUtils to return FsDataset-agnostic
     replica. (Tony Wu via lei)
 
+    HDFS-9377. Fix findbugs warnings in FSDirSnapshotOp.
+    (Mingliang Liu via Yongjun Zhang)
+
   OPTIMIZATIONS
 
     HDFS-8026. Trace FSOutputSummer#writeChecksumChunks rather than

hadoop-hdfs-project/hadoop-hdfs/src/main/java/org/apache/hadoop/hdfs/server/namenode/FSDirSnapshotOp.java

@@ -171,8 +171,7 @@ class FSDirSnapshotOp {
   static Collection<String> getSnapshotFiles(FSDirectory fsd,
       List<DirectorySnapshottableFeature> lsf,
       String file) throws IOException {
-    ArrayList<String> snaps = new ArrayList<String>();
-    ListIterator<DirectorySnapshottableFeature> sfi = lsf.listIterator();
+    ArrayList<String> snaps = new ArrayList<>();
     for (DirectorySnapshottableFeature sf : lsf) {
       // for each snapshottable dir e.g. /dir1, /dir2
       final ReadOnlyList<Snapshot> lsnap = sf.getSnapshotList();