some simple nits.. otherwise looks good.
http://codereview.appspot.com/224074/diff/5/1004 File java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/ConcatProxyServlet.java (right): http://codereview.appspot.com/224074/diff/5/1004#newcode62 java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/ConcatProxyServlet.java:62: Any reason to use transients? I don't think this class will ever be serialized... http://codereview.appspot.com/224074/diff/5/1004#newcode108 java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/ConcatProxyServlet.java:108: if (jsonVar.matches("^\\w*$")) { consider creating a static pattern or use a better word matching pattern StringUtils.isAlphaNum(jsonVar)|| jsonVar.contains("_") may be equiv... http://codereview.appspot.com/224074/diff/5/1004#newcode121 java/gadgets/src/main/java/org/apache/shindig/gadgets/servlet/ConcatProxyServlet.java:121: null check for cos perhaps... http://codereview.appspot.com/224074/show
