diff --git a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseProxy.java b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseProxy.java
index 68cfe9e..667828e 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseProxy.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseProxy.java
@@ -45,7 +45,7 @@
     CompletableFuture<Map<String, Long>> counters();
 
     /**
-     *
+     * Returns the number of entries in map.
      * @param mapName map name
      * @return A completable future to be completed with the result once complete.
      */
diff --git a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseSerializer.java b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseSerializer.java
index 2503cfa..b457b78 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseSerializer.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseSerializer.java
@@ -18,8 +18,6 @@
 
 import java.nio.ByteBuffer;
 
-import org.apache.commons.lang3.tuple.ImmutablePair;
-import org.apache.commons.lang3.tuple.Pair;
 import org.onlab.util.KryoNamespace;
 import org.onosproject.cluster.NodeId;
 import org.onosproject.store.serializers.KryoNamespaces;
@@ -72,8 +70,6 @@
             .register(Versioned.class)
             .register(DatabaseUpdate.class)
             .register(DatabaseUpdate.Type.class)
-            .register(Pair.class)
-            .register(ImmutablePair.class)
             .register(Result.class)
             .register(UpdateResult.class)
             .register(Result.Status.class)
diff --git a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseState.java b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseState.java
index e0582c9..e2e532a 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseState.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DatabaseState.java
@@ -51,7 +51,7 @@
   Map<String, Long> counters();
 
   @Query
-  int size(String mapName);
+  int mapSize(String mapName);
 
   @Query
   boolean mapIsEmpty(String mapName);
diff --git a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultDatabaseState.java b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultDatabaseState.java
index 2a37e53..18ae2c4 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultDatabaseState.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/DefaultDatabaseState.java
@@ -27,7 +27,6 @@
 import java.util.stream.Collectors;
 import java.util.Set;
 
-import org.apache.commons.lang3.tuple.Pair;
 import org.onosproject.cluster.NodeId;
 import org.onosproject.store.service.DatabaseUpdate;
 import org.onosproject.store.service.Transaction;
@@ -112,7 +111,7 @@
     }
 
     @Override
-    public int size(String mapName) {
+    public int mapSize(String mapName) {
       return getMap(mapName).size();
     }
 
@@ -186,7 +185,7 @@
         return ImmutableSet.copyOf(getMap(mapName)
                 .entrySet()
                 .stream()
-                .map(entry -> Pair.of(entry.getKey(), entry.getValue()))
+                .map(entry -> Maps.immutableEntry(entry.getKey(), entry.getValue()))
                 .collect(Collectors.toSet()));
     }
 
diff --git a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/TransactionManager.java b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/TransactionManager.java
index 16e1cdc..db39a46 100644
--- a/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/TransactionManager.java
+++ b/core/store/dist/src/main/java/org/onosproject/store/consistent/impl/TransactionManager.java
@@ -22,8 +22,6 @@
 import java.util.concurrent.CompletableFuture;
 import java.util.stream.Collectors;
 
-import org.apache.commons.lang3.tuple.ImmutablePair;
-import org.apache.commons.lang3.tuple.Pair;
 import org.onlab.util.KryoNamespace;
 import org.onosproject.store.serializers.KryoNamespaces;
 import org.onosproject.store.service.AsyncConsistentMap;
@@ -47,8 +45,6 @@
             .register(DatabaseUpdate.Type.class)
             .register(DefaultTransaction.class)
             .register(Transaction.State.class)
-            .register(Pair.class)
-            .register(ImmutablePair.class)
             .build();
 
     private final Serializer serializer = Serializer.using(Arrays.asList(KRYO_NAMESPACE));
diff --git a/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java b/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
index 2f34408..6784ab3 100644
--- a/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
+++ b/core/store/serializers/src/main/java/org/onosproject/store/serializers/KryoNamespaces.java
@@ -18,6 +18,7 @@
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
 import com.google.common.collect.ImmutableSet;
+import com.google.common.collect.Maps;
 
 import org.onlab.packet.ChassisId;
 import org.onlab.packet.EthType;
@@ -222,6 +223,7 @@
                       LinkedList.class,
                       HashSet.class
                       )
+            .register(Maps.immutableEntry("a", "b").getClass())
             .register(new ArraysAsListSerializer(), Arrays.asList().getClass())
             .register(Collections.singletonList(1).getClass())
             .register(Duration.class)