diff --git a/jetty-http/src/main/java/org/eclipse/jetty/http/HttpFields.java b/jetty-http/src/main/java/org/eclipse/jetty/http/HttpFields.java
index 81eeeaec983..451bc93abef 100644
--- a/jetty-http/src/main/java/org/eclipse/jetty/http/HttpFields.java
+++ b/jetty-http/src/main/java/org/eclipse/jetty/http/HttpFields.java
@@ -682,9 +682,12 @@ public class HttpFields implements Iterable<HttpField>
     
     public void add(HttpField field)
     {
-        if (_size==_fields.length)
-            _fields=Arrays.copyOf(_fields,_size*2);
-        _fields[_size++]=field;
+        if (field!=null)
+        {
+            if (_size==_fields.length)
+                _fields=Arrays.copyOf(_fields,_size*2);
+            _fields[_size++]=field;
+        }
     }
 
     public void addAll(HttpFields fields)
diff --git a/jetty-util/src/main/java/org/eclipse/jetty/util/resource/JarFileResource.java b/jetty-util/src/main/java/org/eclipse/jetty/util/resource/JarFileResource.java
index 32a83568c4a..7d426fff928 100644
--- a/jetty-util/src/main/java/org/eclipse/jetty/util/resource/JarFileResource.java
+++ b/jetty-util/src/main/java/org/eclipse/jetty/util/resource/JarFileResource.java
@@ -55,13 +55,13 @@ class JarFileResource extends JarResource
     protected JarFileResource(URL url, boolean useCaches)
     {
         super(url, useCaches);
-    }
-   
+    }   
 
     /* ------------------------------------------------------------ */
     @Override
     public synchronized void close()
     {
+        _exists=false;
         _list=null;
         _entry=null;
         _file=null;
@@ -144,7 +144,6 @@ class JarFileResource extends JarResource
 
         if (_urlString.endsWith("!/"))
         {
-            
             String file_url=_urlString.substring(4,_urlString.length()-2);
             try{return newResource(file_url).exists();}
             catch(Exception e) {LOG.ignore(e); return false;}