How to Reverse Integer or String Array in Java with Example

There are multiple ways we can perform how to reverse an array in java with example. Reversing an array is an easy question. Let understand the question through the example :

Input    : {3, 8, 5, 7, 4}
Output : {4, 7, 5, 8, 3}

Input     : {10, 54, 23, 89, 97, 2}
Output  : {2, 97, 89, 23, 54, 10}

Read Also :   How to reverse a String in java with Example

The input Array can be a collection of :

1. int primitive data type Array (Method 1)
2. Integer Array (Method2)
3. String Array (Method 3)

Method 1: Code to Reverse int Array in Java

1. Swap the values of left indices with the right indices till the mid element.

    Please find the reverse an array in java image below for  method 1:


Reverse Array in Java with Example
Reverse Array in Java Example


import java.util.*;
public class ReverseArray
{
    public static void main (String[] args) throws java.lang.Exception
    {  
        // Given input array 
        int[] inputArray = {3,7,9,6,4}; 
        // Print array before reverse  
        System.out.println("Array without reverse" + 
                            Arrays.toString(inputArray)); 
        // Calling method to swap elements 
        reverseArray(inputArray);
    }
    public static void reverseArray(int[] inputArray) {
        for (int left = 0, right = inputArray.length - 1; 
                        left < right; left++, right--) {
            // swap the values at the left and right indices
            int temp = inputArray[left];
            inputArray[left]  = inputArray[right];
            inputArray[right] = temp;
        }
        // Printing the Array after reverse  
        System.out.print("Reverse Array :");
        for(int val : inputArray)
            System.out.print(" "+val);
    }
}

Output :
Array without reverse[3, 7, 9, 6, 4]
Reverse Array : 4 6 9 7 3

Method 2: Code to Reverse Integer Array in Java

1. Convert the Integer Array to the list using Arrays.asList() method.
2. Reverse the list using Collections.reverse() method
3. Convert the list back to the array using list.toArray() method.

import java.util.*;
public class ReverseArray
{
    public static void main (String[] args) throws java.lang.Exception
    {  
        // Given input array 
        Integer[] inputArray = {3,7,9,6,4}; 
        // Print array before reverse  
        System.out.println("Array without reverse" + 
                            Arrays.toString(inputArray)); 
        // Calling method to swap elements 
        reverseArray(inputArray);
    }
   public static void reverseArray(Integer[] arr) { 
        // Converting Array to List 
        List<Integer> list = Arrays.asList(arr); 
        // Reversing the list using Collections.reverse() method 
        Collections.reverse(list); 
        // Printing the reverse Array 
        System.out.print("Reverse Array :");
        for(Integer val : list)
            System.out.print(" "+val);
   }
}

Output :
Array without reverse[3, 7, 9, 6, 4]
Reverse Array : 4 6 9 7 3

Method 3: Code to Reverse String Array in Java

1. Convert the String Array to the list using Arrays.asList() method.
2. Reverse the list using Collections.reverse() method
3. Convert the list back to the array using list.toArray() method.

import java.util.*;
public class ReverseArray
{
    public static void main (String[] args) throws java.lang.Exception
    {  
        // Given input array 
        String[] inputArray = {"India","USA","Germany","Australia"}; 
        // Print array before reverse  
        System.out.println("Array without reverse : " + 
                            Arrays.toString(inputArray)); 
        // Calling method to swap elements 
        reverseArray(inputArray);
    }
   public static void reverseArray(String[] arr) {
        // Converting Array to List
        List<String> list = Arrays.asList(arr);
        // Reversing the list using Collections.reverse() method
        Collections.reverse(list);
        // Converting list back to Array
        String[] reversedArray = list.toArray(arr);
        // Printing the reverse Array
        System.out.print("Reverse Array : " + Arrays.toString(reversedArray));
   }
}

Output :
Array without reverse : [India, USA, Germany, Australia]
Reverse Array : [Australia, Germany, USA, India]

Please mention in the comments in case if you have any questions regarding reverse array in java.

About The Author

Subham Mittal has worked in Oracle for 3 years .
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