CombineLists

package Arrays;

import java.util.Scanner;

public class CombineLists {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        String[] firstInput = scanner.nextLine().split(",");
        String[] secondInput = scanner.nextLine().split(",");
        String[] formatArray = new String[firstInput.length * 2];

        int counter = 0;
        for (int i = 0; i < formatArray.length; i += 2) {

            formatArray[i] = firstInput[counter];
            formatArray[i + 1] = secondInput[counter];
            counter++;
        }

        System.out.println(String.join(",", formatArray));
    }
}