LGTM Looks fantastic. Just one nit, commit at will after.
http://codereview.appspot.com/3734041/diff/115002/java/gadgets/src/main/java/org/apache/shindig/gadgets/uri/DefaultConcatUriManager.java File java/gadgets/src/main/java/org/apache/shindig/gadgets/uri/DefaultConcatUriManager.java (right): http://codereview.appspot.com/3734041/diff/115002/java/gadgets/src/main/java/org/apache/shindig/gadgets/uri/DefaultConcatUriManager.java#newcode115 java/gadgets/src/main/java/org/apache/shindig/gadgets/uri/DefaultConcatUriManager.java:115: float injectedMaxUrlLength = ConcatData.getMaxUrlLength() * URL_LENGTH_BUFFER_MARGIN; you can probably just cast this to an int http://codereview.appspot.com/3734041/
