Index: xwiki-core/src/main/java/com/xpn/xwiki/web/JsxAction.java
===================================================================
--- xwiki-core/src/main/java/com/xpn/xwiki/web/JsxAction.java	(revision 18291)
+++ xwiki-core/src/main/java/com/xpn/xwiki/web/JsxAction.java	(working copy)
@@ -62,8 +62,8 @@
 
         if (context.getRequest().getParameter("resource") != null) {
             sxSource = new SxResourceSource(context.getRequest().getParameter("resource"));
-        }
-
+        } 
+        
         else {
             if (context.getDoc().isNew()) {
                 context.getResponse().setStatus(HttpServletResponse.SC_NOT_FOUND);
@@ -71,8 +71,13 @@
             }
             sxSource = new SxDocumentSource(context, sxType);
         }
-
-        super.renderExtension(sxSource, sxType, context);
+        
+        try {
+        	super.renderExtension(sxSource, sxType, context);
+        } catch (NullPointerException e) {
+        	context.getResponse().setStatus(HttpServletResponse.SC_NOT_FOUND);
+            return "docdoesnotexist";
+        }
         return null;
     }
 
Index: xwiki-core/src/main/java/com/xpn/xwiki/web/SsxAction.java
===================================================================
--- xwiki-core/src/main/java/com/xpn/xwiki/web/SsxAction.java	(revision 18291)
+++ xwiki-core/src/main/java/com/xpn/xwiki/web/SsxAction.java	(working copy)
@@ -56,8 +56,8 @@
     @Override
     public String render(XWikiContext context) throws XWikiException
     {
-
-        SxSource sxSource;
+    	
+    	SxSource sxSource;
 
         Extension sxType = new CssExtension();
 
@@ -73,7 +73,13 @@
             sxSource = new SxDocumentSource(context, sxType);
         }
 
-        super.renderExtension(sxSource, sxType, context);
+                
+        try {
+        	super.renderExtension(sxSource, sxType, context);
+        } catch (NullPointerException e) {
+        	context.getResponse().setStatus(HttpServletResponse.SC_NOT_FOUND);
+            return "docdoesnotexist";
+        }
         return null;
     }
 
Index: xwiki-core/src/main/java/com/xpn/xwiki/web/sx/SxResourceSource.java
===================================================================
--- xwiki-core/src/main/java/com/xpn/xwiki/web/sx/SxResourceSource.java	(revision 18291)
+++ xwiki-core/src/main/java/com/xpn/xwiki/web/sx/SxResourceSource.java	(working copy)
@@ -68,6 +68,8 @@
         try {
             InputStream in = this.getClass().getResourceAsStream("/" + this.resourceName);
             return IOUtils.toString(in);
+        } catch (NullPointerException e) {
+        	throw e;
         } catch (IOException e) {
             return "";
         }