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This article introduces the relevant knowledge of "Function functional interface and functional interface examples of Java8". In the operation of actual cases, many people will encounter such a dilemma, so let the editor lead you to learn how to deal with these situations. I hope you can read it carefully and be able to achieve something!

A functional interface (Functional Interface) is an interface that has one and only one abstract method, but can have multiple non-abstract methods.

Functional interfaces can be implicitly converted to lambda expressions.

Functional interfaces can support lambda amicably with existing functions.

Introduction

A functional interface is actually an abstract interface class. The functional interfaces that existed before Java 8 include the following.

Java.lang.Runnablejava.util.concurrent.Callablejava.util.Comparator

Wait a minute.

Usage

In fact, the interface class mentioned above only needs to be modified with FunctionalInterface annotations to become a functional interface in Java. For example, Callable interface definition in JDK

@ FunctionalInterfacepublic interface Callable {V call () throws Exception;}

It's that simple.

Now let's talk about the new Function interface in Java 8. Here is the definition

/ / T is the incoming parameter / / R is the return parameter @ FunctionalInterfacepublic interface Function {R apply (T t); default Function compose (Function)

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