Learning RxJava

Making a Runnable a lambda

Prior to Java 8, you might have leveraged anonymous classes to implement interfaces, such as Runnable, on the fly as shown in the following code snippet:

public class Launcher {    public static void main(String[] args) {        Runnable runnable = new Runnable() {            @Override            public void run() {                System.out.println("run() was called!");            }        };        runnable.run();    }}

The output is as follows:

run() was called!

To implement Runnable without declaring an explicit class, you had to implement its run() abstract method in a block immediately after the constructor. This created a lot of boilerplate and became a major pain point with Java development, and was a barrier to using Java for functional programming. Thankfully, Java 8 officially ...