Lambda expressions helps avoiding a lot of boiler plate code and makes the life of a developer a lot easier. It helps programmers write very simple, less complex code. Nobody likes writing more lines of code ! Lambda expressions helps you avoid anonymous inner classes and instead provide the equivalent of it as plain expressions. Here is a good video tutorial on understanding Lambda.
Video : Java 8 Lambda Basic Syntax – Udemy course excerpt
Reference : Toby Weston , Youtube Video