diff --git a/core/src/main/java/org/springframework/security/core/userdetails/UserDetails.java b/core/src/main/java/org/springframework/security/core/userdetails/UserDetails.java
index 643706e3cf..fa0381c318 100644
--- a/core/src/main/java/org/springframework/security/core/userdetails/UserDetails.java
+++ b/core/src/main/java/org/springframework/security/core/userdetails/UserDetails.java
@@ -53,7 +53,7 @@ public interface UserDetails extends Serializable {
     Collection<? extends GrantedAuthority> getAuthorities();
 
     /**
-     * Returns the password used to authenticate the user. Cannot return <code>null</code>.
+     * Returns the password used to authenticate the user.
      *
      * @return the password
      */