Java- homework- understand code using listener interface and extract code necessary to run one scraper at a time

I have with me code for a java web application, which implements a run time listener. I want you to change the code for this class so that it runs exactly one process of the scraper. After your changes, there should be a single function, which I can invoke to execute one scraper.('Scraper' is the class having a run time listener). I also want you to create a document explaining the existing code. I should be able to understand clearly how the code works. For the purpose of this document assume that I am a java beginner. The relevant sections of code are attached with this bid request. Regards, Arvind.