Sorting an ArrayList of objects using a custom sorting order in java

 Sorting an ArrayList of objects using a custom sorting order in java

Do Check My Video On Utility Classes:

Example:

import java.util.ArrayList;

import java.util.Collections;

import java.util.Comparator;

import java.util.Iterator;

public class Test{

    public static void main(String[] args) {

        ArrayList al = new ArrayList();

        al.add(25);

        al.add(35);

        al.add(15);

        al.add(5);

        al.add(40);

        System.out.println(al);//[25, 35, 15, 5, 40]

        Collections.sort(al);

        System.out.println(al);//[5, 15, 25, 35, 40]

        System.out.println(Collections.binarySearch(al,15,new MyComparator()));//1

        System.out.println(Collections.binarySearch(al,5,new MyComparator()));//0

        System.out.println(Collections.binarySearch(al,17));//-3

    }

}

class MyComparator implements Comparator{

    public int compare(Object obj1,Object obj2){

        Integer i1 = (Integer) obj1;

        Integer i2 = (Integer) obj2;

        return i1.compareTo(i2);

    }

}

o/p:

[25, 35, 15, 5, 40]

[5, 15, 25, 35, 40]

1

0

-3