新手需要帮助理解java代码

I'm very new to the java programming language and I would really like some help understanding what the following code is doing. I have a pretty decent understanding of what is going on within the Main class. My problem is what part "this._" plays within the code. How exactly are the names getting transferred? This is not homework just self study. The exercise can be found here:I'm very new to the java programming language a