Call collections Sort() method, compare two person objects (by age ratio first, and by name ratio for the same age), and pass lambda expression as a parameter.

call Collections.sort() Method , Compare the two Person object （ First by age , The same age by name ）, Use Lambda The expression is passed as an argument . 

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

    public Person(String name, int age) {
        this.name = name;
        this.age = age;
    }
    // rewrite toString Method 
    @Override
    public String toString() {
        return "Person{" +
                "name='" + name + '\'' +
                ", age=" + age +
                '}';
    }
}

import java.util.Arrays;
import java.util.Collections;
import java.util.List;

public class Test {
    public static void main(String[] args) {

        List<Person> list = Arrays.asList(new Person(" Xiao Liang ", 22),
                new Person(" Li Si ", 23), new Person(" Xiao Ming ", 20),
                new Person(" Zhang San ", 20));
        //sort  Method passes in a comparator   Comparator<? super T> c
        Collections.sort(list,(a, b) ->{
            int num = Integer.compare(a.age, b.age);
            int num2 = num==0?a.name.compareTo(b.name):num;
            return  num2; // Be sure to write when there are multiline expressions return
        });
        for (Person employee : employeeList) {
            System.out.println(employee.toString());
        }

    }
}

Running results ：