Sort collection by object property in Java

A lot of time, we are sorting something in our applications. Sort numbers, sort string, etc. What about when we are sorting objects with their property. For example, you have a person class and you have a list of persons. And you need to sort this list by age property of person.

There is a lot of samples on developer forums about sorting for different programming languages. I want to show, how can you do this by Comparator in a few lines of code.

Let's go.

We have a Person class :

public class Person {
    public String FirstName;
    public String LastName;
    public Integer Age;
}

And have a person list :

    List<Person> persons;

How to sort persons list by age property ?

Collections.sort(persons, new Comparator<Person>() {
    public int compare(Person p1, Person p2) {
        return p1.Age.compareTo(p2.Age);
    }
});

That's all. You have sorted persons list.