Welcome to the website of Davis Fiore

Lambda expressions are anonymous functions. They have been introduced in Java 8 to represent functional interfaces. A functional interface is an interface with a single abstract method.

Three parts are required:

	functional interface = arguments -> lambda expression

Here are some examples.

1) A simple lambda expression, represented by a native functional interface with an abstract method, without arguments:

	Runnable runnable = () -> System.out.println("Hello");

2) Here's an example with a custom interface:

	public interface Doable {

		void doIt(String s);
				
	}

The expression is assigned with one parameter:

	Doable doable = (String s) -> System.out.println(s);

You can then call the implementation of the interface, passing the expected parameter:

	doable.doIt("Hello");

3) Here is an other example with the above interface, but this time the functional interface is a method argument.

	
	public void myMethod(Doable a) {
		a.doIt("Hello");
	}

The method is called in that way:

	myMethod((String s) -> System.out.println(s));

4) Most of the time you don't even need to write your own functional interface, because Java 8 provides the package java.util.function with some general-use interfaces, using generics. Here is an example with the interface Consumer:

	public void myMethod(Consumer<String> a) {
		a.accept("Hello");
	}

The method is called in that way:

	myMethod((String sd) -> System.out.println(sd));