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CollectionsExample.java

import java.util.ArrayList;
import java.util.Collections;

/*
 Example of:  

 swap(List<?> list, int i, int j)

 Parameters:

 list - The list in which to swap elements.
 i - the index of one element to be swapped.
 j - the index of the other element to be swapped.

 */

public class CollectionsExample
{

    public static void main(String[] args)
    {

        ArrayList<Integer> arrayList = new ArrayList<Integer>();

        arrayList.add(2000);
        arrayList.add(3000);
        arrayList.add(4000);
        arrayList.add(1000);

        System.out.println("arrayList : " + arrayList + "\n");

        /*
         * Swaps the elements at the specified positions in the specified list.
         * (If the specified positions are equal, invoking this method leaves
         * the list unchanged.)
         */

        Collections.swap(arrayList, 0, 1);

        System.out.println("After Swap , arrayList : " + arrayList + "\n");

    }

}