java 新手提问

[Rookiekk]

import java.util.*;

public class Welcome {
    public static void main(String[] args) {
    	new Person().printPerson();//这两行为什么会错
    	new Student().printPerson();
    
    }
    class Student extends Person{
    	@Override
    	public String getInfo(){
    		return "student";
    	}
    }
    class Person{
    	public String getInfo(){
    		return "person";
    	}
    	public void printPerson(){
    		System.out.println(getInfo());
    	}
	    }
}

为什么会错呢。我是按书上打上去的
另外我换成这些之后还是不对
Person p = new Person();
Student s = new Student();
p.printPerson();
s.printPerson();
错误原因都是这些
No enclosing instance of type Welcome is accessible. Must qualify the allocation with an enclosing instance of type Welcome (e.g. x.new A()
where x is an instance of Welcome).

[李德胜1995]

把两个类拉倒外面。。。。