diff --git a/hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupSystemTable.java b/hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupSystemTable.java
index de3ccc759c3..76e104610c4 100644
--- a/hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupSystemTable.java
+++ b/hbase-backup/src/main/java/org/apache/hadoop/hbase/backup/impl/BackupSystemTable.java
@@ -21,6 +21,7 @@ import java.io.Closeable;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;
@@ -28,6 +29,7 @@ import java.util.List;
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.Set;
+import java.util.stream.Collectors;
 import java.util.TreeMap;
 import java.util.TreeSet;
 
@@ -62,6 +64,7 @@ import org.apache.hadoop.hbase.client.SnapshotDescription;
 import org.apache.hadoop.hbase.client.Table;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.BackupProtos;
 import org.apache.hadoop.hbase.shaded.protobuf.generated.HBaseProtos;
+import org.apache.hadoop.hbase.util.ArrayUtils;
 import org.apache.hadoop.hbase.util.Bytes;
 import org.apache.hadoop.hbase.util.EnvironmentEdgeManager;
 import org.apache.hadoop.hbase.util.Pair;
@@ -530,9 +533,8 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException exception
    */
   public String readBackupStartCode(String backupRoot) throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("read backup start code from backup system table");
-    }
+    LOG.trace("read backup start code from backup system table");
+
     try (Table table = connection.getTable(tableName)) {
       Get get = createGetForStartCode(backupRoot);
       Result res = table.get(get);
@@ -570,9 +572,8 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException
    */
   public void startBackupExclusiveOperation() throws IOException {
-    if (LOG.isDebugEnabled()) {
-      LOG.debug("Start new backup exclusive operation");
-    }
+    LOG.debug("Start new backup exclusive operation");
+
     try (Table table = connection.getTable(tableName)) {
       Put put = createPutForStartBackupSession();
       // First try to put if row does not exist
@@ -593,9 +594,8 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public void finishBackupExclusiveOperation() throws IOException {
-    if (LOG.isDebugEnabled()) {
-      LOG.debug("Finish backup exclusive operation");
-    }
+    LOG.debug("Finish backup exclusive operation");
+
     try (Table table = connection.getTable(tableName)) {
       Put put = createPutForStopBackupSession();
       if (!table.checkAndPut(ACTIVE_SESSION_ROW, SESSIONS_FAMILY, ACTIVE_SESSION_COL,
@@ -619,9 +619,7 @@ public final class BackupSystemTable implements Closeable {
    */
   public HashMap<String, Long> readRegionServerLastLogRollResult(String backupRoot)
       throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("read region server last roll log result to backup system table");
-    }
+    LOG.trace("read region server last roll log result to backup system table");
 
     Scan scan = createScanForReadRegionServerLastLogRollResult(backupRoot);
 
@@ -650,9 +648,8 @@ public final class BackupSystemTable implements Closeable {
    */
   public void writeRegionServerLastLogRollResult(String server, Long ts, String backupRoot)
       throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("write region server last roll log result to backup system table");
-    }
+    LOG.trace("write region server last roll log result to backup system table");
+
     try (Table table = connection.getTable(tableName)) {
       Put put = createPutForRegionServerLastLogRollResult(server, ts, backupRoot);
       table.put(put);
@@ -666,12 +663,10 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException exception
    */
   public ArrayList<BackupInfo> getBackupHistory(boolean onlyCompleted) throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("get backup history from backup system table");
-    }
-    ArrayList<BackupInfo> list;
+    LOG.trace("get backup history from backup system table");
+
     BackupState state = onlyCompleted ? BackupState.COMPLETE : BackupState.ANY;
-    list = getBackupInfos(state);
+    ArrayList<BackupInfo> list = getBackupInfos(state);
     return BackupUtils.sortHistoryListDesc(list);
   }
 
@@ -692,15 +687,11 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException
    */
   public List<BackupInfo> getHistory(int n) throws IOException {
-
     List<BackupInfo> history = getBackupHistory();
-    if (n == -1 || history.size() <= n) return history;
-    List<BackupInfo> list = new ArrayList<BackupInfo>();
-    for (int i = 0; i < n; i++) {
-      list.add(history.get(i));
+    if (n == -1 || history.size() <= n) {
+      return history;
     }
-    return list;
-
+    return Collections.unmodifiableList(history.subList(0, n));
   }
 
   /**
@@ -742,10 +733,11 @@ public final class BackupSystemTable implements Closeable {
     Set<TableName> names = new HashSet<>();
     List<BackupInfo> infos = getBackupHistory(true);
     for (BackupInfo info : infos) {
-      if (info.getType() != type) continue;
-      names.addAll(info.getTableNames());
+      if (info.getType() == type) {
+        names.addAll(info.getTableNames());
+      }
     }
-    return new ArrayList(names);
+    return new ArrayList<>(names);
   }
 
   /**
@@ -815,9 +807,7 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException exception
    */
   public ArrayList<BackupInfo> getBackupInfos(BackupState state) throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("get backup infos from backup system table");
-    }
+    LOG.trace("get backup infos from backup system table");
 
     Scan scan = createScanForBackupHistory();
     ArrayList<BackupInfo> list = new ArrayList<BackupInfo>();
@@ -946,9 +936,8 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException exception
    */
   public Set<TableName> getIncrementalBackupTableSet(String backupRoot) throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("get incremental backup table set from backup system table");
-    }
+    LOG.trace("get incremental backup table set from backup system table");
+
     TreeSet<TableName> set = new TreeSet<>();
 
     try (Table table = connection.getTable(tableName)) {
@@ -977,9 +966,9 @@ public final class BackupSystemTable implements Closeable {
     if (LOG.isTraceEnabled()) {
       LOG.trace("Add incremental backup table set to backup system table. ROOT=" + backupRoot
           + " tables [" + StringUtils.join(tables, " ") + "]");
-      for (TableName table : tables) {
-        LOG.debug(table);
-      }
+    }
+    if (LOG.isDebugEnabled()) {
+      tables.forEach(table -> LOG.debug(table));
     }
     try (Table table = connection.getTable(tableName)) {
       Put put = createPutForIncrBackupTableSet(tables, backupRoot);
@@ -1014,9 +1003,9 @@ public final class BackupSystemTable implements Closeable {
     if (LOG.isTraceEnabled()) {
       LOG.trace("add WAL files to backup system table: " + backupId + " " + backupRoot + " files ["
           + StringUtils.join(files, ",") + "]");
-      for (String f : files) {
-        LOG.debug("add :" + f);
-      }
+    }
+    if (LOG.isDebugEnabled()) {
+      files.forEach(file -> LOG.debug("add :" + file));
     }
     try (Table table = connection.getTable(tableName)) {
       List<Put> puts = createPutsForAddWALFiles(files, backupId, backupRoot);
@@ -1030,9 +1019,8 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException exception
    */
   public Iterator<WALItem> getWALFilesIterator(String backupRoot) throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("get WAL files from backup system table");
-    }
+    LOG.trace("get WAL files from backup system table");
+
     final Table table = connection.getTable(tableName);
     Scan scan = createScanForGetWALs(backupRoot);
     final ResultScanner scanner = table.getScanner(scan);
@@ -1096,10 +1084,7 @@ public final class BackupSystemTable implements Closeable {
     try (Table table = connection.getTable(tableName)) {
       Get get = createGetForCheckWALFile(file);
       Result res = table.get(get);
-      if (res.isEmpty()) {
-        return false;
-      }
-      return true;
+      return (!res.isEmpty());
     }
   }
 
@@ -1110,9 +1095,8 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException exception
    */
   public boolean hasBackupSessions() throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("Has backup sessions from backup system table");
-    }
+    LOG.trace("Has backup sessions from backup system table");
+
     boolean result = false;
     Scan scan = createScanForBackupHistory();
     scan.setCaching(1);
@@ -1135,9 +1119,8 @@ public final class BackupSystemTable implements Closeable {
    * @throws IOException
    */
   public List<String> listBackupSets() throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace(" Backup set list");
-    }
+    LOG.trace("Backup set list");
+
     List<String> list = new ArrayList<String>();
     Table table = null;
     ResultScanner scanner = null;
@@ -1180,7 +1163,8 @@ public final class BackupSystemTable implements Closeable {
       if (res.isEmpty()) return null;
       res.advance();
       String[] tables = cellValueToBackupSet(res.current());
-      return toList(tables);
+      return Arrays.asList(tables).stream().map(item -> TableName.valueOf(item)).
+        collect(Collectors.toList());
     } finally {
       if (table != null) {
         table.close();
@@ -1188,14 +1172,6 @@ public final class BackupSystemTable implements Closeable {
     }
   }
 
-  private List<TableName> toList(String[] tables) {
-    List<TableName> list = new ArrayList<TableName>(tables.length);
-    for (String name : tables) {
-      list.add(TableName.valueOf(name));
-    }
-    return list;
-  }
-
   /**
    * Add backup set (list of tables)
    * @param name set name
@@ -1206,10 +1182,8 @@ public final class BackupSystemTable implements Closeable {
     if (LOG.isTraceEnabled()) {
       LOG.trace("Backup set add: " + name + " tables [" + StringUtils.join(newTables, " ") + "]");
     }
-    Table table = null;
     String[] union = null;
-    try {
-      table = connection.getTable(tableName);
+    try (Table table = connection.getTable(tableName)) {
       Get get = createGetForBackupSet(name);
       Result res = table.get(get);
       if (res.isEmpty()) {
@@ -1221,28 +1195,9 @@ public final class BackupSystemTable implements Closeable {
       }
       Put put = createPutForBackupSet(name, union);
       table.put(put);
-    } finally {
-      if (table != null) {
-        table.close();
-      }
     }
   }
 
-  private String[] merge(String[] tables, String[] newTables) {
-    List<String> list = new ArrayList<String>();
-    // Add all from tables
-    for (String t : tables) {
-      list.add(t);
-    }
-    for (String nt : newTables) {
-      if (list.contains(nt)) continue;
-      list.add(nt);
-    }
-    String[] arr = new String[list.size()];
-    list.toArray(arr);
-    return arr;
-  }
-
   /**
    * Remove tables from backup set (list of tables)
    * @param name set name
@@ -1254,11 +1209,9 @@ public final class BackupSystemTable implements Closeable {
       LOG.trace(" Backup set remove from : " + name + " tables [" + StringUtils.join(toRemove, " ")
           + "]");
     }
-    Table table = null;
     String[] disjoint = null;
     String[] tables = null;
-    try {
-      table = connection.getTable(tableName);
+    try (Table table = connection.getTable(tableName)) {
       Get get = createGetForBackupSet(name);
       Result res = table.get(get);
       if (res.isEmpty()) {
@@ -1280,27 +1233,19 @@ public final class BackupSystemTable implements Closeable {
         LOG.info("Backup set '" + name + "' is empty. Deleting.");
         deleteBackupSet(name);
       }
-    } finally {
-      if (table != null) {
-        table.close();
-      }
     }
   }
 
-  private String[] disjoin(String[] tables, String[] toRemove) {
-    List<String> list = new ArrayList<String>();
-    // Add all from tables
-    for (String t : tables) {
-      list.add(t);
-    }
-    for (String nt : toRemove) {
-      if (list.contains(nt)) {
-        list.remove(nt);
-      }
-    }
-    String[] arr = new String[list.size()];
-    list.toArray(arr);
-    return arr;
+  private String[] merge(String[] existingTables, String[] newTables) {
+    Set<String> tables = new HashSet<>(Arrays.asList(existingTables));
+    tables.addAll(Arrays.asList(newTables));
+    return tables.toArray(new String[0]);
+  }
+
+  private String[] disjoin(String[] existingTables, String[] toRemove) {
+    Set<String> tables = new HashSet<>(Arrays.asList(existingTables));
+    Arrays.asList(toRemove).forEach(table -> tables.remove(table));
+    return tables.toArray(new String[0]);
   }
 
   /**
@@ -1312,15 +1257,9 @@ public final class BackupSystemTable implements Closeable {
     if (LOG.isTraceEnabled()) {
       LOG.trace(" Backup set delete: " + name);
     }
-    Table table = null;
-    try {
-      table = connection.getTable(tableName);
+    try (Table table = connection.getTable(tableName)) {
       Delete del = createDeleteForBackupSet(name);
       table.delete(del);
-    } finally {
-      if (table != null) {
-        table.close();
-      }
     }
   }
 
@@ -1606,7 +1545,6 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public static void snapshot(Connection conn) throws IOException {
-
     try (Admin admin = conn.getAdmin();) {
       Configuration conf = conn.getConfiguration();
       admin.snapshot(BackupSystemTable.getSnapshotName(conf), BackupSystemTable.getTableName(conf));
@@ -1614,7 +1552,6 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public static void restoreFromSnapshot(Connection conn) throws IOException {
-
     Configuration conf = conn.getConfiguration();
     LOG.debug("Restoring " + BackupSystemTable.getTableNameAsString(conf) + " from snapshot");
     try (Admin admin = conn.getAdmin();) {
@@ -1635,7 +1572,6 @@ public final class BackupSystemTable implements Closeable {
   }
 
   protected static boolean snapshotExists(Admin admin, String snapshotName) throws IOException {
-
     List<SnapshotDescription> list = admin.listSnapshots();
     for (SnapshotDescription desc : list) {
       if (desc.getName().equals(snapshotName)) {
@@ -1650,7 +1586,6 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public static void deleteSnapshot(Connection conn) throws IOException {
-
     Configuration conf = conn.getConfiguration();
     LOG.debug("Deleting " + BackupSystemTable.getSnapshotName(conf) + " from the system");
     try (Admin admin = conn.getAdmin();) {
@@ -1669,7 +1604,7 @@ public final class BackupSystemTable implements Closeable {
    */
   static List<Put> createPutForPreparedBulkload(TableName table, byte[] region,
       final byte[] family, final List<Pair<Path, Path>> pairs) {
-    List<Put> puts = new ArrayList<>();
+    List<Put> puts = new ArrayList<>(pairs.size());
     for (Pair<Path, Path> pair : pairs) {
       Path path = pair.getSecond();
       String file = path.toString();
@@ -1689,7 +1624,7 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public static List<Delete> createDeleteForOrigBulkLoad(List<TableName> lst) {
-    List<Delete> lstDels = new ArrayList<>();
+    List<Delete> lstDels = new ArrayList<>(lst.size());
     for (TableName table : lst) {
       Delete del = new Delete(rowkey(BULK_LOAD_PREFIX, table.toString(), BLK_LD_DELIM));
       del.addFamily(BackupSystemTable.META_FAMILY);
@@ -1699,7 +1634,6 @@ public final class BackupSystemTable implements Closeable {
   }
 
   private Put createPutForDeleteOperation(String[] backupIdList) {
-
     byte[] value = Bytes.toBytes(StringUtils.join(backupIdList, ","));
     Put put = new Put(DELETE_OP_ROW);
     put.addColumn(META_FAMILY, FAM_COL, value);
@@ -1707,14 +1641,12 @@ public final class BackupSystemTable implements Closeable {
   }
 
   private Delete createDeleteForBackupDeleteOperation() {
-
     Delete delete = new Delete(DELETE_OP_ROW);
     delete.addFamily(META_FAMILY);
     return delete;
   }
 
   private Get createGetForDeleteOperation() {
-
     Get get = new Get(DELETE_OP_ROW);
     get.addFamily(META_FAMILY);
     return get;
@@ -1731,9 +1663,8 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public void finishDeleteOperation() throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("Finsih delete operation for backup ids ");
-    }
+    LOG.trace("Finsih delete operation for backup ids");
+
     Delete delete = createDeleteForBackupDeleteOperation();
     try (Table table = connection.getTable(tableName)) {
       table.delete(delete);
@@ -1741,9 +1672,8 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public String[] getListOfBackupIdsFromDeleteOperation() throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("Get delete operation for backup ids ");
-    }
+    LOG.trace("Get delete operation for backup ids");
+
     Get get = createGetForDeleteOperation();
     try (Table table = connection.getTable(tableName)) {
       Result res = table.get(get);
@@ -1760,7 +1690,6 @@ public final class BackupSystemTable implements Closeable {
   }
 
   private Put createPutForMergeOperation(String[] backupIdList) {
-
     byte[] value = Bytes.toBytes(StringUtils.join(backupIdList, ","));
     Put put = new Put(MERGE_OP_ROW);
     put.addColumn(META_FAMILY, FAM_COL, value);
@@ -1771,15 +1700,11 @@ public final class BackupSystemTable implements Closeable {
     Get get = new Get(MERGE_OP_ROW);
     try (Table table = connection.getTable(tableName)) {
       Result res = table.get(get);
-      if (res.isEmpty()) {
-        return false;
-      }
-      return true;
+      return (!res.isEmpty());
     }
   }
 
   private Put createPutForUpdateTablesForMerge(List<TableName> tables) {
-
     byte[] value = Bytes.toBytes(StringUtils.join(tables, ","));
     Put put = new Put(MERGE_OP_ROW);
     put.addColumn(META_FAMILY, PATH_COL, value);
@@ -1787,14 +1712,12 @@ public final class BackupSystemTable implements Closeable {
   }
 
   private Delete createDeleteForBackupMergeOperation() {
-
     Delete delete = new Delete(MERGE_OP_ROW);
     delete.addFamily(META_FAMILY);
     return delete;
   }
 
   private Get createGetForMergeOperation() {
-
     Get get = new Get(MERGE_OP_ROW);
     get.addFamily(META_FAMILY);
     return get;
@@ -1821,9 +1744,8 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public void finishMergeOperation() throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("Finsih merge operation for backup ids ");
-    }
+    LOG.trace("Finish merge operation for backup ids");
+
     Delete delete = createDeleteForBackupMergeOperation();
     try (Table table = connection.getTable(tableName)) {
       table.delete(delete);
@@ -1831,9 +1753,8 @@ public final class BackupSystemTable implements Closeable {
   }
 
   public String[] getListOfBackupIdsFromMergeOperation() throws IOException {
-    if (LOG.isTraceEnabled()) {
-      LOG.trace("Get backup ids for merge operation");
-    }
+    LOG.trace("Get backup ids for merge operation");
+
     Get get = createGetForMergeOperation();
     try (Table table = connection.getTable(tableName)) {
       Result res = table.get(get);
@@ -1917,8 +1838,7 @@ public final class BackupSystemTable implements Closeable {
   private List<Put>
       createPutsForAddWALFiles(List<String> files, String backupId, String backupRoot)
           throws IOException {
-
-    List<Put> puts = new ArrayList<Put>();
+    List<Put> puts = new ArrayList<Put>(files.size());
     for (String file : files) {
       Put put = new Put(rowkey(WALS_PREFIX, BackupUtils.getUniqueWALFileNamePart(file)));
       put.addColumn(BackupSystemTable.META_FAMILY, Bytes.toBytes("backupId"),
@@ -2021,11 +1941,10 @@ public final class BackupSystemTable implements Closeable {
    */
   private String[] cellValueToBackupSet(Cell current) throws IOException {
     byte[] data = CellUtil.cloneValue(current);
-    if (data != null && data.length > 0) {
+    if (!ArrayUtils.isEmpty(data)) {
       return Bytes.toString(data).split(",");
-    } else {
-      return new String[0];
     }
+    return new String[0];
   }
 
   /**
diff --git a/hbase-backup/src/test/java/org/apache/hadoop/hbase/backup/TestBackupSystemTable.java b/hbase-backup/src/test/java/org/apache/hadoop/hbase/backup/TestBackupSystemTable.java
index 5814d87aa0d..ee5f9b9f186 100644
--- a/hbase-backup/src/test/java/org/apache/hadoop/hbase/backup/TestBackupSystemTable.java
+++ b/hbase-backup/src/test/java/org/apache/hadoop/hbase/backup/TestBackupSystemTable.java
@@ -29,6 +29,7 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.HashSet;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Set;
@@ -369,11 +370,14 @@ public class TestBackupSystemTable {
       String[] addTables = new String[] { "table4", "table5", "table6" };
       table.addToBackupSet(setName, addTables);
 
+      Set<String> expectedTables = new HashSet<>(Arrays.asList("table1", "table2", "table3",
+        "table4", "table5", "table6"));
+
       List<TableName> tnames = table.describeBackupSet(setName);
       assertTrue(tnames != null);
-      assertTrue(tnames.size() == tables.length + addTables.length);
-      for (int i = 0; i < tnames.size(); i++) {
-        assertTrue(tnames.get(i).getNameAsString().equals("table" + (i + 1)));
+      assertTrue(tnames.size() == expectedTables.size());
+      for (TableName tableName : tnames) {
+        assertTrue(expectedTables.remove(tableName.getNameAsString()));
       }
       cleanBackupTable();
     }
@@ -389,11 +393,14 @@ public class TestBackupSystemTable {
       String[] addTables = new String[] { "table3", "table4", "table5", "table6" };
       table.addToBackupSet(setName, addTables);
 
+      Set<String> expectedTables = new HashSet<>(Arrays.asList("table1", "table2", "table3",
+        "table4", "table5", "table6"));
+
       List<TableName> tnames = table.describeBackupSet(setName);
       assertTrue(tnames != null);
-      assertTrue(tnames.size() == tables.length + addTables.length - 1);
-      for (int i = 0; i < tnames.size(); i++) {
-        assertTrue(tnames.get(i).getNameAsString().equals("table" + (i + 1)));
+      assertTrue(tnames.size() == expectedTables.size());
+      for (TableName tableName : tnames) {
+        assertTrue(expectedTables.remove(tableName.getNameAsString()));
       }
       cleanBackupTable();
     }
@@ -409,11 +416,13 @@ public class TestBackupSystemTable {
       String[] removeTables = new String[] { "table4", "table5", "table6" };
       table.removeFromBackupSet(setName, removeTables);
 
+      Set<String> expectedTables = new HashSet<>(Arrays.asList("table1", "table2", "table3"));
+
       List<TableName> tnames = table.describeBackupSet(setName);
       assertTrue(tnames != null);
-      assertTrue(tnames.size() == tables.length - 1);
-      for (int i = 0; i < tnames.size(); i++) {
-        assertTrue(tnames.get(i).getNameAsString().equals("table" + (i + 1)));
+      assertTrue(tnames.size() == expectedTables.size());
+      for (TableName tableName : tnames) {
+        assertTrue(expectedTables.remove(tableName.getNameAsString()));
       }
       cleanBackupTable();
     }
@@ -429,11 +438,13 @@ public class TestBackupSystemTable {
       String[] removeTables = new String[] { "table4", "table3" };
       table.removeFromBackupSet(setName, removeTables);
 
+     Set<String> expectedTables = new HashSet<>(Arrays.asList("table1", "table2"));
+
       List<TableName> tnames = table.describeBackupSet(setName);
       assertTrue(tnames != null);
-      assertTrue(tnames.size() == tables.length - 2);
-      for (int i = 0; i < tnames.size(); i++) {
-        assertTrue(tnames.get(i).getNameAsString().equals("table" + (i + 1)));
+      assertTrue(tnames.size() == expectedTables.size());
+      for (TableName tableName : tnames) {
+        assertTrue(expectedTables.remove(tableName.getNameAsString()));
       }
       cleanBackupTable();
     }