diff --git a/Library/src/main/java/com/anupcowkur/reservoir/ReservoirGetCallback.java b/Library/src/main/java/com/anupcowkur/reservoir/ReservoirGetCallback.java
index 372b28d..66ce3e4 100644
--- a/Library/src/main/java/com/anupcowkur/reservoir/ReservoirGetCallback.java
+++ b/Library/src/main/java/com/anupcowkur/reservoir/ReservoirGetCallback.java
@@ -1,14 +1,7 @@
 package com.anupcowkur.reservoir;
 
-/**
- *
- */
-public abstract class ReservoirGetCallback<T> {
-    public void onSuccess(T object) {
+public interface ReservoirGetCallback<T> {
+    public void onSuccess(T object);
 
-    }
-
-    public void onFailure(Exception e) {
-
-    }
+    public void onFailure(Exception e);
 }
diff --git a/Library/src/main/java/com/anupcowkur/reservoir/ReservoirPutCallback.java b/Library/src/main/java/com/anupcowkur/reservoir/ReservoirPutCallback.java
index baf4ae1..0ca81a6 100644
--- a/Library/src/main/java/com/anupcowkur/reservoir/ReservoirPutCallback.java
+++ b/Library/src/main/java/com/anupcowkur/reservoir/ReservoirPutCallback.java
@@ -1,14 +1,7 @@
 package com.anupcowkur.reservoir;
 
-/**
- *
- */
-public abstract class ReservoirPutCallback {
-    public void onSuccess() {
+public interface ReservoirPutCallback {
+    public void onSuccess();
 
-    }
-
-    public void onFailure(Exception e) {
-
-    }
+    public void onFailure(Exception e);
 }