继承：子类、父类

package com.extendsDemo;

public class Test {
    public static void main(String[] args) {
        B b=new B();
        System.out.println(b.i);
        // System.out.println(b.j);//报错

        b.prin1();
        b.print3();
        // b.print2();//报错
    }
}

package com.extendsDemo;
//父类
public class A {
    //公开成员
    public int i;
    public void prin1(){
        System.out.println("===print1===");
    }

    //私有成员
    private int j;
    private void prin2(){
        System.out.println("===print2===");
    }

}

package com.extendsDemo;
//子类
public class B extends A{
    //子类是可以继承父类的非私有成员
    public void print3(){
        System.out.println(i);
        prin1();

       // System.out.println(j);//报错
      //  prin2();//报错
    }
}