diff --git a/src/test/java/org/apache/commons/collections4/map/IdentityMap.java b/src/test/java/org/apache/commons/collections4/map/IdentityMap.java
index 17321010d..50736a898 100644
--- a/src/test/java/org/apache/commons/collections4/map/IdentityMap.java
+++ b/src/test/java/org/apache/commons/collections4/map/IdentityMap.java
@@ -184,7 +184,11 @@ public class IdentityMap<K, V>
     }
 
     /**
-     * Read the map in using a custom routine.
+     * Deserializes an instance from an ObjectInputStream.
+     *
+     * @param in The source ObjectInputStream.
+     * @throws IOException            Any of the usual Input/Output related exceptions.
+     * @throws ClassNotFoundException A class of a serialized object cannot be found.
      */
     private void readObject(final ObjectInputStream in) throws IOException, ClassNotFoundException {
         in.defaultReadObject();