import java.util.Scanner;

public class LoopTest {

    public static void main(String[] args) {

        boolean repeat;

        do {

            Scanner keyboard = new Scanner(System.in);
            char answer;
            boolean invalid = true;


            System.out.print("Please type something: ");
            String input = keyboard.nextLine();
            System.out.println("You said: " + input);

            System.out.println("Again? y/n");
            input = keyboard.nextLine();
            answer = input.charAt(0);

            while (invalid) {

                if (answer == 'y' || answer == 'n') {

                    invalid = false;

                } else {

                    System.out.println("Please enter y or n.");
                    input = keyboard.nextLine();
                    answer = input.charAt(0);

                }
            }

            if (answer == 'y') {

                repeat = true;

            } else {

                repeat = false;

            }

        } while(repeat);

        System.exit(0);

    }

}