How to implement our own pair data structure in Java

PairsTest.java

import java.util.HashSet;
import java.util.Map;
import java.util.Objects;
import java.util.Set;

public class PairsTest {
    static class IntPair {
        int x, y;
        public IntPair(int a, int b) {
            this.x = a;
            this.y = b;
        }

        @Override
        public boolean equals(Object o) {
            IntPair ip = (IntPair) o;
            return this.x == ip.x && this.y == ip.y;
        }

        @Override
        public int hashCode() {
            return Objects.hash(this.x, this.y);
            //return (String.valueOf(this.x) + String.valueOf(this.y)).hashCode();
        }
    }
    public static void main(String []args) {
        //Creating a custom pair class is the first choice, because the code is readable
        //We need to remember implementing the equals and hashCode method.
        Set<IntPair> intPairs= new HashSet<>();
        intPairs.add(new IntPair(0, 1));
        intPairs.add(new IntPair(1, 2));
        intPairs.add(new IntPair(0, 1));
        intPairs.add(new IntPair(0, 2));

        for(IntPair pair: intPairs) {
            System.out.println(pair.x + " " + pair.y);
        }
        System.out.println();

        //The following approach using arrays does not work and there is no easy way to make it work.
        /*
        Set<int[]> intArraySet = new HashSet<>();
        int []arr1 = {0, 1};
        int []arr2 = {1, 2};

        intArraySet.add(new int[]{0, 1});
        intArraySet.add(new int[]{1, 2});
        intArraySet.add(new int[]{0, 1});

        intArraySet.add(arr1);
        intArraySet.add(arr2);
        intArraySet.add(arr1);

        for(int[] pair: intArraySet) {
            System.out.println(pair[0] + " " + pair[1]);
        }
        System.out.println();
        */

        //Another way to create a pair is to utilize Map.Entry class in Java standard library
        Set<Map.Entry<Integer, Integer>> entries = new HashSet<>();
        entries.add(Map.entry(0, 1));
        entries.add(Map.entry(1, 2));
        entries.add(Map.entry(0, 1));
        entries.add(Map.entry(0, 2));

        for(Map.Entry<Integer, Integer> entry: entries) {
            System.out.println(entry.getKey() + " " + entry.getValue());
        }
    }
}