Functional Interfaces from Scratch
In this video, we learn about creating function-like objects using lambdas and functional interfaces. From scratch, we create an interface called RealFunction that specifies one method, public double call(double x). This creates a type that can accept a lambda as an assignment.
Functional interfaces are a huge part of being a 21st century Java programmer. They eliminate a lot of boiler plate code and make such things as event handling simple.