diff --git a/hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/security/authentication/util/AuthToken.java b/hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/security/authentication/util/AuthToken.java
index 844501c678c30..5a585a684fb6f 100644
--- a/hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/security/authentication/util/AuthToken.java
+++ b/hadoop-common-project/hadoop-auth/src/main/java/org/apache/hadoop/security/authentication/util/AuthToken.java
@@ -24,6 +24,8 @@
 import java.util.StringTokenizer;
 
 /**
+ * {@link AuthToken} contains information about authenticated and can double
+ * as a {@link Principal} return.
  */
 public class AuthToken implements Principal {