Q:

CORS HTTP header not showing on GAE Java

I have a custom domain setup on GAE that is hosting a java web (servlet) application, I need to support XHR requests from a different app domain so I attempted to set the CORS response header both programmatically and as instructed in GAE reference docs for java but I am unable to see the header in the response and my XHR requests fail.
The following code is implemented in the servlet's doPost, doGet, doOptions methods.
response.setContentType("application/json");
response.addHeader("Access-Control-Allow-Origin:", "*");

I also attempted to set the header in the appengine-web.xml file as follows.
<static-files>
   <include path="https://api.ezpzrentals.com/validate" >
       <http-header name="Access-Control-Allow-Origin" value="*" />
   </include>
 </static-files>

Neither of the above seem to be working, any tips would be greatly appreciated!

A:

After reviewing carefully, this was a dumb mistake on my part, there is a colon ":" at the end of the header and GAE obviously does not like that, what threw me off is that in my local dev instance, it was showing up.

