Check out these links:

Basic tutorial on the for statement

The while and do-while statements

Example Code

import java.util.InputMismatchException;
import java.util.Scanner;


/**
 * Uses scanner to ask user for a number [n] and a character input [c]. Outputs
 * the character input [c], [n] times to console.
 * 
 * @author Zobit
 *
 */
public class Main
{
    Scanner scan;
    char c;
    int n;

    /**
     * Constructor. Necessary to initialize the field variables and to work with
     * the class in a non-static context.
     */
    public Main()
    {
        scan = new Scanner(System.in); // System.in for console input.
        c = 0;
        n = 0;
    }

    /**
     * Nothing special. Just the main method to execute our program
     * 
     * @param args
     */
    public static void main(String[] args)
    {
        Main m = new Main();
        m.performPrintLoop();
    }

    // Public access method. Ensures all methods are called in correct order.
    // Added in case we want to use this functionality outside of the class in
    // the future
    public void performPrintLoop()
    {
        askForNumber();
        askForCharacter();
        printLoop();
    }

    /**
     * Uses a while-loop to get a number input from the user.
     */
    private void askForNumber()
    {
        boolean hasNumber = false;
        // while-loops run continually until their condition is no longer valid.
        // Our condition states while not hasNumber, which was set to false, so
        // by default it will be running as soon as the method has been invoked.
        while (!hasNumber)
        {
            // Use a try-catch in case of bad user input.
            try
            {
                System.out.println("Please input a non-decimal positive number greater than 0");
                n = scan.nextInt();
                if (n <= 0)
                    throw new InputMismatchException();
                hasNumber = true;
            } catch (InputMismatchException e)
            {
                scan.nextLine(); // advance the scanner past bad input
            }
        }
    }

    /**
     * Same logic as askForNumber, but try to get a character.
     */
    private void askForCharacter()
    {
        boolean hasCharacter = false;
        while (!hasCharacter)
        {
            try
            {
                System.out.println("Please input a single character");
                String in = scan.next();
                if (in.length() > 1)
                    throw new InputMismatchException();
                c = in.charAt(0);
                hasCharacter = true;
            } catch (InputMismatchException e)
            {
                scan.nextLine();
            }
        }
    }

    /**
     * A simple for-loop to print out the character c, n times.
     */
    private void printLoop()
    {
        System.out.println("Printing \"" + c + "\" " + n + " times\n\n");
        for (int i = 0; i < n; i++)
        {
            System.out.println(c);
        }
    }

}