import java.util.ArrayList; import java.util.Comparator; import java.util.List; public class Main { public static void main(String[] args) { List<Person> people = new ArrayList<Person>(); people.add(new Person("C", 21)); people.add(new Person("T", 20)); people.add(new Person("B", 35)); people.add(new Person("A", 22)); people.sort(Comparator.comparing(Person::getName)); people.forEach(System.out::println); } } class Person { private String name; private int age; public Person(String name, int age){ this.name = name; this.age = age; } public String getName() { return this.name; } public int getAge() { return this.age; } @Override public String toString(){ return this.name + " (" + this.age + ")"; } }