I get “Source not found” when debugging my Java code in Eclipse

Question

I\'m trying to debug my Java application in Eclipse however when I hit a breakpoint I simply see the following instead of my source:

Answer 1

When I faced this problem for the very first time, I've already done all the steps mentioned here. Curiously, my problem happened when I've copied a project into another place. Anyway, the debug starts to work without warnings, after simply remove all breakpoints that was originated from the original project. Sorry about my English , I'm not fluent.