Reverse an Array In Place

/*
 * Problem : Process an array.
 * Input   : n, then n integers.
 * Output  : The reversed array.
 * Approach: Two pointers.
 * Time    : O(n)
 * Space   : O(1)
 * Java    : 8 or newer.
 */
import java.util.Scanner;
import java.util.Arrays;
import java.util.stream.Collectors;

public class Main {
    // This method solves the task. It receives the input and returns the answer.
    static int[] solve(int[] a) {
        // Step 1: One pointer at the start and one at the end.
        int left = 0;
        int right = a.length - 1;

        // Step 2: Swap the two elements, then move both pointers to the middle. Stop when they meet.
        while (left < right) {
            int temporary = a[left];
            a[left] = a[right];
            a[right] = temporary;
            left++;
            right--;
        }
        return a;
    }

    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int size = scanner.nextInt();
        int[] a = new int[size];
        for (int i = 0; i < size; i++) {
            a[i] = scanner.nextInt();
        }
        System.out.println(Arrays.stream(solve(a)).mapToObj(String::valueOf).collect(Collectors.joining(" ")));
    }
}