Fix Javadoc warnings

Change-Id: Ia5fe7785f76da92abbf940599cbd3d7dc6ac2cc5
diff --git a/core/store/persistence/src/main/java/org/onosproject/persistence/impl/PersistenceException.java b/core/store/persistence/src/main/java/org/onosproject/persistence/impl/PersistenceException.java
index 7056f50..047a1f7 100644
--- a/core/store/persistence/src/main/java/org/onosproject/persistence/impl/PersistenceException.java
+++ b/core/store/persistence/src/main/java/org/onosproject/persistence/impl/PersistenceException.java
@@ -22,6 +22,8 @@
 public class PersistenceException extends RuntimeException {
     /**
      * Throws an exception with the specified message.
+     *
+     * @param s message for exception
      */
     public PersistenceException(String s) {
         super(s);