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how to reverse contents of arraylist java?


ArrayList:

ArrayList class extends AbstractList and implements the List interface. It uses dynamic arrays for storing elements. It maintains insertion order. ArrayList can contain duplicate elements. It is not synchronized.

Note: ArrayList provides the facility of random access because of it is index based.

We can use Collections.reverse() method to reverse contents of arraylist in java.

Example:

package com.codesjava;
 
import java.util.ArrayList;
import java.util.Collections;
 
public class Test {
  public static void main(String args[]){
	ArrayList<String> arrayList = new ArrayList<String>();
	arrayList.add("Jai");
	arrayList.add("Mahesh");
	arrayList.add("Vivek");
	arrayList.add("Naren");
	arrayList.add("Hemant");
	arrayList.add("Vishal");
	System.out.println("Actual ArrayList:"+arrayList);
	Collections.reverse(arrayList);
        System.out.println("ArrayList after reverse operation:" + arrayList);
  }
}

Output

Actual ArrayList:[Jai, Mahesh, Vivek, Naren, Hemant, Vishal]
ArrayList after reverse operation:[Vishal, Hemant, Naren, Vivek, Mahesh, Jai]
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