CHelper is a wonderful tool, especially for this site.
It is a plugin in IDEA (IntelliJ) which converts several files into one java source file. So it allows us to have code in several files/classes (you know, best practices and all), and automatically merge them into one source file.
Just not so long ago, I struggled with how to use it. So now that I got it working, I thought I could share the process with you.
It is here http://stackoverflow.com/a/38634234/2589983 in my answer to my own question.