Reverse an Array in Java 8 Using IntStream

Learn how to reverse an array in Java 8 using IntStream.rangeClosed() with a simple example, step-by-step explanation, and output.

  • Intstream.rangeClosed(1, a.length) generates numbers from 1 to the length of the array.
  • The map() method is used to access array elements in reverse order.
  • a[a.length – n] gets the element from the last index to the first index.
  • The toArray() method converts the stream result into an integer array.
  • Arrays.toString() is used to print the reversed array in readable format.
				
					import java.util.Arrays;
import java.util.stream.IntStream;

public class ReverseArrayTest {
    public static void main(String[] args) {
        int[] a = { 2, 3, 1, 1, 4, 3, 2, 5 };

        int[] value = IntStream.rangeClosed(1, a.length)
                .map(n -> a[a.length - n])
                .toArray();

        System.out.println("Reverse array value is :- " + Arrays.toString(value));
    }
}

Output :
Reverse array value is :- [5, 2, 3, 4, 1, 1, 3, 2]

Java 8 Program to Reverse an Array

				
					
mport java.util.Arrays;
import java.util.Collections;

public class ReverseArrayWithoutRangeClosed {
    public static void main(String[] args) {

        Integer[] arr = { 2, 3, 1, 1, 4, 3, 2, 5 };

        Collections.reverse(Arrays.asList(arr));

        System.out.println("Reverse array value is :- " + Arrays.toString(arr));
    }
}

Output :
Reverse array value is :- [5, 2, 3, 4, 1, 1, 3, 2]

FAQ

  • How do you reverse an array in Java 8?

          You can reverse an array in Java 8 by using IntStream.rangeClosed() and accessing array elements            from the last index to the first index.

  • Can we reverse an int array using Java 8 Stream API?

           Yes, we can reverse an int array using Java 8 Stream API with IntStream and the map() method.

  • What is the use of Arrays.toString() in this program?

           Arrays.toString() is used to convert the array into a readable string format for printing.

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