diff --git a/modules/grizzly/src/main/java/org/glassfish/grizzly/utils/Holder.java b/modules/grizzly/src/main/java/org/glassfish/grizzly/utils/Holder.java
index b54545bb4..25c30171b 100644
--- a/modules/grizzly/src/main/java/org/glassfish/grizzly/utils/Holder.java
+++ b/modules/grizzly/src/main/java/org/glassfish/grizzly/utils/Holder.java
@@ -69,7 +69,7 @@ protected int evaluate() {
     @Override
     public String toString() {
         final E obj = get();
-        return obj != null ? "{" + obj + "}" : null;
+        return obj != null ? "{" + obj + "}" : "{}";
     }
 
     public static abstract class LazyHolder<E> extends Holder<E> {