I tried so many things like clean - rebuild, removing all the references and add them again, changing target APIs. But it was not working. App never started.
After doing failed attempt for almost half an hour, it came to my attention that src folder in project was a simple folder. There was no package sign on it and when I explore it, all my packages where turned into folders and sub folders and that was the issue. My src folder was not a sources folder and because of that it was unable to found a class.
So to solve this issue. Right click on src folder Select Java Build Path - > Use as a source folder.
And that's it all the folders and sub folders in the src folder turned into packages and application was working fine. Hope this helps you and save your time.