Java – How to Reverse Order of elements in ArrayList ?

In this article, we will discuss how to reverse order of elements in List using Collections class’s utility reverse() method

Reversing order of elements of Java ArrayList

Method signature:

public static void reverse(List<Object> list);

ReverseArrayListContents.java

package in.bench.resources.java.collection;

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

public class ReverseArrayListContents {

	public static void main(String[] args) {

		// creating ArrayList object of type String
		ArrayList<String> al = new ArrayList<String>();

		// adding elements to ArrayList object
		al.add("Narayan Murthy");
		al.add("Dinesh");
		al.add("Nandan Nilekeni");
		al.add("Ashok Arora");
		al.add("Shibulal");
		al.add("Kris Gopalakrishnan");
		al.add("Raghavan");

		System.out.println("Insertion order:"
				+ " Iterating ArrayList values\n");

		// Iterating using enhanced for-loop
		for(String str : al){
			System.out.println(str);
		}

		// reverse ordering of ArrayList
		// using Collections.reverse(al);
		Collections.reverse(al);

		System.out.println("\n\nReverse Insertion order:"
				+ " after reversing using Collections.reverse(al)\n");

		// Iterating using enhanced for-loop
		for(String str : al){
			System.out.println(str);
		}
	}
}

Output:

Insertion order: Iterating ArrayList values

Narayan Murthy
Dinesh
Nandan Nilekeni
Ashok Arora
Shibulal
Kris Gopalakrishnan
Raghavan

Reverse Insertion order: after reversing using Collections.reverse(al)

Raghavan
Kris Gopalakrishnan
Shibulal
Ashok Arora
Nandan Nilekeni
Dinesh
Narayan Murthy

Related Articles:

References:

Happy Coding !!
Happy Learning !!

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