diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreSize.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreSize.java
index cf2ef6fe600..557a61a49c7 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreSize.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreSize.java
@@ -62,7 +62,7 @@ public class MemStoreSize {
 
   @Override
   public boolean equals(Object obj) {
-    if (obj == null || !(obj instanceof MemStoreSize)) {
+    if (obj == null || getClass() != obj.getClass()) {
       return false;
     }
     MemStoreSize other = (MemStoreSize) obj;
diff --git a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreSizing.java b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreSizing.java
index fade6222513..b13201d4a23 100644
--- a/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreSizing.java
+++ b/hbase-server/src/main/java/org/apache/hadoop/hbase/regionserver/MemStoreSizing.java
@@ -82,7 +82,7 @@ public class MemStoreSizing extends MemStoreSize {
 
   @Override
   public boolean equals(Object obj) {
-    if (obj == null || !(obj instanceof MemStoreSizing)) {
+    if (obj == null || (getClass() != obj.getClass())) {
       return false;
     }
     MemStoreSizing other = (MemStoreSizing) obj;