Easy Solution

class Result {

/*
 * Complete the 'findDay' function below.
 *
 * The function is expected to return a STRING.
 * The function accepts following parameters:
 *  1. INTEGER month
 *  2. INTEGER day
 *  3. INTEGER year
 */

public static String findDay(int month, int day, int year) {

    Calendar calendar = Calendar.getInstance();

    calendar.set(year,month-1,day);

    System.out.println(calendar.getTime());

    int res = calendar.get(calendar.DAY_OF_WEEK);

    switch (res) {
        case 1 -> {return "SUNDAY";}
        case 2 -> {return "MONDAY";}
        case 3 -> {return "TUESDAY";}
        case 4 -> {return "WEDNESDAY";}
        case 5 -> {return "THURSDAY";}
        case 6 -> {return "FRIDAY";}
        case 7 -> {return "SATURDAY";}
        default -> {return "nachobc";}
    }

}

}