I am working on the SP2013 On premise provider hosted app (app + user policy), and I need to implement code to upload large files using CSOM. But before we could upload large files, I would like to get the set upload file limit on web application. 

Can someone inform if it is possible to get the "Maximum upload size" web application property by CSOM code. 

Hi

You can`t. The Client Object Model (CSOM) does not provide access above the Site Collection level.

As far as I know, the only way to do what you want is to create a custom web service that gets the Web Application information using the Server Object Model and have the remote application use it instead of the CSOM.

http://sharepoint.stackexchange.com/questions/75157/how-to-get-all-the-web-application-of-sharepoint