To be or not to be functional, with examples

Functional programming has been slowly accepted as the new programming paradigm that tries to solve several issues concerning software design and development. Java 1.8 has introduced the new functional API in 2014, but people and companies are still reluctant to adopt functional programming in Java projects as a coding standard equal to classic imperative coding. My personal interests lie in helping developers write good and clean code and I believe functional programming is one of the means to achieve this goal. This presentation will use a simple business case to show how it can be done using classic style of programming, and what to expect when trying to write it using functional code at the beginner level and at the intermediate level. Produced code will be analyzed and compared from the standpoint of someone who needs to understand and maintain the code. The simplest algorithm should be the best one. This overview will hopefully bring more projects into adopting functional programming standard.