diff --git a/google-oauth-client/src/main/java/com/google/api/client/auth/oauth/OAuthCredentialsResponse.java b/google-oauth-client/src/main/java/com/google/api/client/auth/oauth/OAuthCredentialsResponse.java
index 7a679e8f8..6fe86530b 100644
--- a/google-oauth-client/src/main/java/com/google/api/client/auth/oauth/OAuthCredentialsResponse.java
+++ b/google-oauth-client/src/main/java/com/google/api/client/auth/oauth/OAuthCredentialsResponse.java
@@ -25,7 +25,7 @@
  * @author Yaniv Inbar
  */
 @Beta
-public final class OAuthCredentialsResponse {
+public final class OAuthCredentialsResponse extends HashMap<String, Object> {
 
   /** Credentials token. */
   @Key("oauth_token")