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How to sort an array of objects?

package com.javacoderanch.examples.util;

import java.util.Arrays;

public class ObjectSortExample {
    public static void main(String[] args) {
        // Here we have a list of people name, it is balinese people
        // name.
        String names[] = {"Wayan", "Made", "Nyoman", "Ketut"};

        // We can order them by their name and write to the screen. 
        // It's just like sorting a primitive array.
        for (int i = 0; i < names.length; i++) {
            String name = names[i];
            System.out.print("name = " + name + "; ");

        // Now we will sort an array of our own object. It is a bit
        // different compared to sorting an array of primitives. The
        // first rule is we need our object to implements the 
        // Comparable interface. This interface have one contract we
        // need to implement, the compareTo() contract. See the Person 
        // class below.
        // Here we create four Person objects, and set their name.
        // After that we sort the Person object based on their name 
        // using the Arrays.sort() method.
        Person persons[] = new Person[4];
        persons[0] = new Person("Wayan");
        persons[1] = new Person("Made");
        persons[2] = new Person("Nyoman");
        persons[3] = new Person("Ketut");

        for (int i = 0; i < persons.length; i++) {
            Person person = persons[i];
            System.out.println("person = " + person);

// As mentioned above that to be sortable by Arrays.sort() method our
// class need to implements the compareTo(Object obj) method which is
// a contract defined in the Comparable interface.
class Person implements Comparable {
    private String name;

    // A constructor to Person class.
    public Person(String name) { = name;

    // Here is our compareTo implementation, here we just delegate
    // the compareTo to the string object compareTo method. The basic
    // rule for this method to return are: 0 when objects value are
    // equals; 1 if this object value is greater; and -1 if this object
    // value is smaller.
    public int compareTo(Object o) {
        Person p = (Person) o;

    // Override toString() to return a readable person name.
    public String toString() {
        return name;