diff --git a/common/source/java/ch/systemsx/cisd/common/collections/UnmodifiableCollectionDecorator.java b/common/source/java/ch/systemsx/cisd/common/collections/UnmodifiableCollectionDecorator.java
index 6f944807eeae8fe4b4bcc80d806f48fad465daf1..c9fe7d354feea779b4c96a96d62a270bcbaaee0e 100644
--- a/common/source/java/ch/systemsx/cisd/common/collections/UnmodifiableCollectionDecorator.java
+++ b/common/source/java/ch/systemsx/cisd/common/collections/UnmodifiableCollectionDecorator.java
@@ -65,6 +65,12 @@ public class UnmodifiableCollectionDecorator<E> implements Collection<E>
         return collection.hashCode();
     }
 
+    @Override
+    public String toString()
+    {
+        return collection.toString();
+    }
+
     public boolean isEmpty()
     {
         return collection.isEmpty();