Ordinary internal classes
There are two main points to master for ordinary internal classes
Holding the parent class reference, so You can access variables and methods with any access rights of the parent class
How to create internal classes outside the parent class
public class Main{ public static void main(String args[]){ Outer outer = new Outer(); //外部类外部创建内部类 Outer.Inner inner = outer.new Inner(); inner.method(); } } class Outer{ private String value = "OuterValue"; class Inner{ public void method(){ //持有父类引用,可以访问父类private变量value System.out.println(value); } //利用.this关键字,可以返回父类对象引用 public Outer outerObject(){ return Outer.this; } } }
(Recommended tutorial: java entry program)
Method inner class
The inner class directly defined in the method
enjoys the same permissions as the method and access other methods and member variables of the outer class.
You can access the parameters of this method. After 1.8, the parameters do not need to be set to final
Have the same permissions as the local variables of the method, and can access the local variables defined before it
The method inner class can only be accessed in the method scope
public class Main{ public static void main(String args[]){ Outer outer = new Outer(); outer.outerMethod("param"); } } class Outer{ public void outerMethod(String value){ class Inner { public void innerMethod(){ //可以访问方法参数 //1.8以后,内部类访问的方法参数不必设置为final System.out.println(value); } } new Inner().innerMethod(); } }
Anonymous inner class
Anonymous inner class is actually a key point, and it is also a knowledge point we often use .
For example, creating a new thread
public class Main{ public static void main(String args[]){ Thread a = new Thread(new Runnable(){ @Override public void run(){ System.out.println("thread a is running;"); } }); a.start(); } }
The above code means to create an anonymous class object that implements the Runnable interface, which is equivalent to the following code. Due to the convenience of writing, we often use the second one
public class Main{ public static void main(String args[]){ Thread a = new Thread(new RunnableImp()); a.start(); } static class RunnableImp implements Runnable{ @Override public void run(){ System.out.println("thread a is running;"); } } }
Static inner class
Remember the following two points
To create a static inner class object, you do not need an object of the outer class (ordinary inner classes require )
Cannot access non-static external class methods or member variables from static inner classes
public class Main{ Outer.Inner inner = new Outer.Inner(); } class Outer{ private String ordValue; private static String staValue; static class Inner{ { System.out.println(staValue); //这句编译通不过 //System.out.println(ordValue); } } }
Related video tutorial recommendations:java video
The above is the detailed content of Detailed explanation of Java internal classes. For more information, please follow other related articles on the PHP Chinese website!

本篇文章给大家带来了关于java的相关知识,其中主要介绍了关于结构化数据处理开源库SPL的相关问题,下面就一起来看一下java下理想的结构化数据处理类库,希望对大家有帮助。

本篇文章给大家带来了关于java的相关知识,其中主要介绍了关于PriorityQueue优先级队列的相关知识,Java集合框架中提供了PriorityQueue和PriorityBlockingQueue两种类型的优先级队列,PriorityQueue是线程不安全的,PriorityBlockingQueue是线程安全的,下面一起来看一下,希望对大家有帮助。

本篇文章给大家带来了关于java的相关知识,其中主要介绍了关于java锁的相关问题,包括了独占锁、悲观锁、乐观锁、共享锁等等内容,下面一起来看一下,希望对大家有帮助。

本篇文章给大家带来了关于java的相关知识,其中主要介绍了关于多线程的相关问题,包括了线程安装、线程加锁与线程不安全的原因、线程安全的标准类等等内容,希望对大家有帮助。

本篇文章给大家带来了关于Java的相关知识,其中主要介绍了关于关键字中this和super的相关问题,以及他们的一些区别,下面一起来看一下,希望对大家有帮助。

本篇文章给大家带来了关于java的相关知识,其中主要介绍了关于枚举的相关问题,包括了枚举的基本操作、集合类对枚举的支持等等内容,下面一起来看一下,希望对大家有帮助。

封装是一种信息隐藏技术,是指一种将抽象性函式接口的实现细节部分包装、隐藏起来的方法;封装可以被认为是一个保护屏障,防止指定类的代码和数据被外部类定义的代码随机访问。封装可以通过关键字private,protected和public实现。

本篇文章给大家带来了关于java的相关知识,其中主要介绍了关于设计模式的相关问题,主要将装饰器模式的相关内容,指在不改变现有对象结构的情况下,动态地给该对象增加一些职责的模式,希望对大家有帮助。


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

AI Hentai Generator
Generate AI Hentai for free.

Hot Article

Hot Tools

DVWA
Damn Vulnerable Web App (DVWA) is a PHP/MySQL web application that is very vulnerable. Its main goals are to be an aid for security professionals to test their skills and tools in a legal environment, to help web developers better understand the process of securing web applications, and to help teachers/students teach/learn in a classroom environment Web application security. The goal of DVWA is to practice some of the most common web vulnerabilities through a simple and straightforward interface, with varying degrees of difficulty. Please note that this software

SublimeText3 Mac version
God-level code editing software (SublimeText3)

PhpStorm Mac version
The latest (2018.2.1) professional PHP integrated development tool

Safe Exam Browser
Safe Exam Browser is a secure browser environment for taking online exams securely. This software turns any computer into a secure workstation. It controls access to any utility and prevents students from using unauthorized resources.

Zend Studio 13.0.1
Powerful PHP integrated development environment
