diff --git a/json-path/src/main/java/com/jayway/jsonpath/Criteria.java b/json-path/src/main/java/com/jayway/jsonpath/Criteria.java
index 5234c3a1..c13d6391 100644
--- a/json-path/src/main/java/com/jayway/jsonpath/Criteria.java
+++ b/json-path/src/main/java/com/jayway/jsonpath/Criteria.java
@@ -247,7 +247,7 @@ public class Criteria implements Predicate {
                 if(target != null){
                     res = pattern.matcher(target.toString()).matches();
                 }
-                if(logger.isDebugEnabled()) logger.debug("[{}] {} [{}] => {}", right.toString(), name(), left.toString(), res);
+                if(logger.isDebugEnabled()) logger.debug("[{}] {} [{}] => {}", right == null?"null":right.toString(), name(), left==null?"null":left.toString(), res);
                 return res;
             }
             @Override