diff --git a/jetty-server/src/main/java/org/eclipse/jetty/server/ResourceService.java b/jetty-server/src/main/java/org/eclipse/jetty/server/ResourceService.java
index 8ece91dc2f5..1b85ead9665 100644
--- a/jetty-server/src/main/java/org/eclipse/jetty/server/ResourceService.java
+++ b/jetty-server/src/main/java/org/eclipse/jetty/server/ResourceService.java
@@ -836,10 +836,10 @@ public class ResourceService
             r.putHeaders(content, contentLength, _etags);
             HttpFields fields = r.getHttpFields();
             if (_acceptRanges && !fields.contains(HttpHeader.ACCEPT_RANGES))
-                    fields.put(ACCEPT_RANGES);
+                    fields.add(ACCEPT_RANGES);
 
             if (_cacheControl != null && !fields.contains(HttpHeader.CACHE_CONTROL))
-                fields.put(_cacheControl);
+                fields.add(_cacheControl);
         }
         else
         {