I use Johnny server with activated Java support. I created a Java web app. I call a servlet by a link in the index.jsp This is my web: http://danghh92.heliohost.org/ I run my app at localhost. There was no problem. Then, I unzipped the war file. I uploaded all unzipped files to public_html folder. The problem is: I can get the index page. But when I click on the link to call servlet, the 404 error appear. I have tested this app on another hosting. There was no problem. How can I solve this problem?