What is the self-help doctrine? When is this used in criminal law?

Please I need 3 paragraphs in your owe words

Is this a battle or core competencies or just a price war? Walmart vs Amazon

Here are some recent developments in the Walmart-Amazon fight? How should Walmart compete? How should Amazon stave off Walmart’s attacks? Who is likely to win/lose in this rivalry?

http://www.cnbc.com/2017/04/05/amazon-worth-twice-wal-mart.html

https://www.forbes.com/forbes/welcome/?toURL=https://www.forbes.com/sites/walterloeb/2017/04/17/walmart-cuts-hq-staff-fights-amazon-with-new-discounts/&refURL=https://www.google.com/&referrer=https://www.google.com/

https://www.thestreet.com/story/14094522/1/walmart-has-really-stuck-it-to-amazon-with-its-intent-to-slash-prices-on-one-million-products.html

http://www.businessinsider.com/walmart-has-2-huge-advantages-that-should-terrify-amazon-2017-4