Lambda Expressions

Along with the functional improvements in Java 8, there also came Lambda expressions. One of the primary improvements with lambdas is the code readability—most of the boilerplate code for interfaces is now gone.

A very commonly used interface is the Runnable interface; it's used in multithreaded applications to perform any type of task in the background, such as downloading a large file from a network. In Java 7 and earlier versions, you'd often see the Runnable interface used as an anonymous instance:

new Thread(new Runnable() {
    @Override
    public void run() {
    }
}).start();

Since Java 8, the preceding five lines of code can now be simplified by using a lambda expression instead:

new Thread(() -> {}).start();

As you can see, the code becomes much more readable when we remove a lot of the boilerplate code.

The lambda expression consists of two main components...