How do I sort items in a Set? - Learn Java by Examples

The trick to sort a java.util.Set is to use the implementation of a java.util.SortedSet such as the java.util.TreeSet class. The example below shows you the result of using the java.util.TreeSet class, in which the items in it will be sorted based on the element’s natural order.

package org.kodejava.util;

import java.util.Set;
import java.util.TreeSet;

public class TreeSetDemo {
    public static void main(String[] args) {
        // The TreeSet class is an implementation of a SortedSet, this means
        // that when you are using the TreeSet to store you data collections
        // you'll get the items ordered base on its elements natural order.
        Set<String> set = new TreeSet<>();

        // In the example below we add some letters to the TreeSet, this mean
        // that the alphabets will be ordered based on the alphabet order
        // which is from A to Z.
        set.add("Z");
        set.add("A");
        set.add("F");
        set.add("B");
        set.add("H");
        set.add("X");
        set.add("N");

        for (String item : set) {
            System.out.print(item + " ");
        }
    }
}

This demo prints:

A B F H N X Z

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Wayan

Founder at Kode Java

A programmer, runner and recreational diver, lives on the island of Bali, Indonesia. Programming in Java, Spring Framework, Hibernate / JPA, MySQL. To support me working on this project, buy me a cup of coffee, every little bit helps. Thank you.

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