Java Object Oriented 09 (Internal Class)

Inner class

An inner class is to define a class inside a class. For example, if a class B is defined in class A, then class B becomes an inner class relative to class A, and class A is an external class relative to class B.

1. Member inner class
2. Static inner class
3. Local inner class
4. Anonymous inner class

Code example of member inner class:

output example

Example of static inner class code:

static inner class cannot directly access non-static properties

Example of local internal class code:

package com.oop.demo10;

public class Outer {
    private int id=10086 ;//外部类变量
    public void out(){
        System.out.println("这是外部类的方法");
    }
    //定义局部内部类
    public void method(){
        class Inner{
            public void in(){
                System.out.println("这是内部类方法");
            }
        }
    }

}

. Anonymous inner classes Code Example:

package com.oop.demo10;

public class Test {
    public static void main(String[] args) {
        //没有名字初始化类
        new Apple().eat();
    }
}
class Apple{
    public void eat(){
        System.out.println("1");
    }
}

Sample output