java练习，这个return怎么返回多个值

package zhu;

public class Person {
    public String name;
    public int age;
    public String school;
    public String major;

    public void Person1(String n,int a) {
        name =n;
        age=a;
    }
    public double Person1() {
        map.put(name,age);
        return map;
    }

    public void Person2(String n,int a,String s) {
        name =n;
        school=s;
        age=a;
    }
    public double Person2() {
        map.put(name,age,school);
        return map;
    }

    public void Person3(String n,int a,String s,String m) {
        name =n;
        school=s;
        age=a;
        major=m;
    }
    public double Person3() {
        map.put(name,age,school,major);
        return map;
    }
}

package zhu;

public class test {
    public static void main(String[] args){
        Person p=new Person();
        p.Person1("猪",10);
        p.Person2("猪",10,"动物园");
        p.Person3("猪",10,"动物园","大的");

        System.out.println(p.Person1()+p.Person2()+p.Person3());
    }
}

Person p=new Person();
p.Person1("猪",10);
System.out.println(p.Person1());

p.Person2("猪",10,"动物园");
System.out.println(p.Person2());

p.Person3("猪",10,"动物园","大的");
System.out.println(p.Person3());

你这个代码能运行吗，map哪来的，double类型没有put方法