Hi Nader,
I agree with Simon about the CORS issue. With the conding above, you already get around this issues by using the SimpleProxyServlet. But this allows only "local" testing as described here:
https://sapui5.netweaver.ondemand.com/sdk/#docs/guide/TestingInEclipse.html
So as long as you are testing with a browser on your computer, you should be fine. If you access the app from a different computer or mobile device, the SimpleProxyServlet will not work. This is described in the Security Guide posted by Simon:
Proxy Servlet (Java)
SAPUI5 is providing a SimpleProxyServlet. This proxy servlet can be used on a local server only for local requests to access data from other domains. This is useful to avoid cross domain issues when fetching data from another domain for testing purposes. Also for the SAPUI5 tools this is required since the local testing needs to access data from the remote ABAP server. Due to security reasons this proxy servlet is limited to localhost usage only and cannot be used by requests from other domains.
You can check http://scn.sap.com/community/developer-center/front-end/blog/2013/06/29/solving-same-origin-policy-issue-in-different-ways how to get this solved.
Regards, Frank