Program will not loop back until correct

Question

/*Do method to continually ask for correct spelled day until it matches a valid input */
do {   
    System.out.print('\n' + "What is the current Day (Monday-Sunday): ");
    currentDay = stdIn.nextLine();
}while (!(currentDay.equals("Sunday") || currentDay.equals("Monday") || 
          currentDay.equals("Tuesday") || currentDay.equals("Wednesday") ||
          currentDay.equals("Thursday") || currentDay.equals("Friday") || 
          currentDay.equals("Saturday")));

if(!currentDay.equals(dayOfFlight)){
    System.out.println("Today isn't your day for a flight, keep cheching");
}

while (!currentDay.equals(dayOfFlight));

System.out.print("What is the current hour (Military time): ");
int currentHour = stdIn.nextInt();

int time = (hourOfFlight - currentHour);
System.out.println('\n' + "You have " + time + " hours to go.");

Answer 1

Look at your second while:

while (!currentDay.equals(dayOfFlight));

It is like Peter Lawyrey said, "you may have intended to have a second do/while loop where this is the end". The beginning of this second do/while is most likely outside of the first, thus encapsulating the first and executing it until currentDay.equals(dayOfFlight) returns true:

do { // Beginning
    do {
        System.out.print('\n' + "What is the current Day (Monday-Sunday): ");
        currentDay = stdIn.nextLine();
    } while (!(currentDay.equals("Sunday") || currentDay.equals("Monday") || currentDay.equals("Tuesday")
            || currentDay.equals("Wednesday") || currentDay.equals("Thursday") || currentDay.equals("Friday")
            || currentDay.equals("Saturday")));

    if (!currentDay.equals(dayOfFlight)) {
        System.out.println("Today isn't your day for a flight, keep cheching");
        // Don't you mean "keep checking"?
    }

} while (!currentDay.equals(dayOfFlight)); // End

System.out.print("What is the current hour (Military time): ");
int currentHour = stdIn.nextInt();

int time = (hourOfFlight - currentHour);
System.out.println('\n' + "You have " + time + " hours to go.");

On a side note, you might want to change currentDay#equals to currentDay#equalsIgnoreCase and System#print to System#println.

Answer 2

Scanner reader = new Scanner(System.in);
    String currentDay,dayOfFlight="Monday";
    int hourOfFlight=10;
    do {   
         System.out.print('\n' + "What is the current Day (Monday-Sunday): ");
         currentDay = reader.nextLine();


        if(!currentDay.equals(dayOfFlight)){
          System.out.println("Today isn't your day for a flight, keep cheching");
         }
    }

    while (!currentDay.equals(dayOfFlight));

        System.out.print("What is the current hour (Military time): ");
        int currentHour = reader.nextInt();

        int time = (hourOfFlight - currentHour);
        System.out.println('\n' + "You have " + time + " hours to go.");

You doesn't need to use that while loop to check until correct. (if that is what you are trying to achieve.)

Answer 3

Your second while will either do nothing or loop infinitely.

To check this you can step through the code in your debugger.

while (!currentDay.equals(dayOfFlight));

is the same as

while (!currentDay.equals(dayOfFlight)) {
   // nothing changes so loop forever
}

What you may have intended is to have a second do/while loop where this is the end.