Very confused. Help would be appreciated.

import java.text.NumberFormat;
import java.util.Scanner;
import java.util.*;

public class InvoiceApp
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner("r j\n"); //System.in);
        String choice = "y";
        while (!choice.equalsIgnoreCase("n"))
        if(choice.equalsIgnoreCase("y"))    
        {
            // get the input from the user
            String customerType = getValidCustomerType(sc);
            double subtotal = 0.0;
 
            // get the discount percent
            double discountPercent = 0.0;
            if (customerType.equalsIgnoreCase ("r") || customerType.equalsIgnoreCase ("c"))
            {        
                if (customerType.equalsIgnoreCase("R"))
                {
                    try
                    {   
                        subtotal = getValidSubtotal(sc);
                    }
                    catch (InputMismatchException e)
                    {
                        sc.next();
                        System.out.println("1Error! Invalid number. Try again.\n");
                        continue;
                    }   
                    if (subtotal < 100)
                        discountPercent = 0;
                    else if (subtotal >= 100 && subtotal < 250)
                        discountPercent = .1;
                    else if (subtotal >= 250)
                        discountPercent = .2;
                }
                else if (customerType.equalsIgnoreCase("C"))
                {
                    try
                    {   
                        subtotal = getValidSubtotal(sc);
                    }
                    catch (InputMismatchException e)
                    {
                        sc.next();
                        System.out.println("2Error! Invalid number. Try again.\n");
                        continue;
                    } 
                    if (subtotal < 250)
                    discountPercent = .2;
                    else
                    discountPercent = .3;
                }
            }    
            else if (customerType != null)
            {    
                sc.nextLine();
                System.out.println("Error! Invalid Customer Type. Please enter either 'r' or 'c' to continue.\n");
                continue;
            }
            // calculate the discount amount and total
            double discountAmount = subtotal * discountPercent;
            double total = subtotal - discountAmount;
            
            // format and display the results
            NumberFormat currency = NumberFormat.getCurrencyInstance();
            NumberFormat percent = NumberFormat.getPercentInstance();
            System.out.println(
                    "Discount percent: " + percent.format(discountPercent) + "\n" +
                    "Discount amount:  " + currency.format(discountAmount) + "\n" +
                    "Total:            " + currency.format(total) + "\n");
            
            // see if the user wants to continue
            System.out.print("Continue? (y/n): ");
            choice = sc.next();
            sc.nextLine();
            System.out.println();
        }
    }
    public static String getValidCustomerType (Scanner sc)
    {
        // get the input from the user
        String customerType = "";
        boolean isValid = false;
        while (isValid == false)
        { 
            System.out.print("Enter customer type (r/c): ");
            if (sc.hasNext())
            {
                customerType = sc.next();
                System.out.println(customerType);           //<<<<<<<<<<<<
                isValid = true;
            }
            else
            {
                sc.nextLine();
                System.out.println("Error! Invalid Customer Type. Please enter either 'r' or 'c' to continue.\n");
            }         
        }
        return customerType;
    }   
    public static double getValidSubtotal (Scanner sc)
    {
        double subtotal = 0.0;
        boolean isValid = false;

        while (isValid == false)
        {
            //get a valid double value
            System.out.print("Enter subtotal:   ");
            if (sc.hasNextDouble())
            {
                subtotal = sc.nextDouble();
                isValid = true;
            }
            else
            {
                String str = sc.nextLine();
                System.out.println(str);        //<<<<<<<<<<<<<
                System.out.println("3Error! Invalid number:"+str+" Try again.\n");
            }    
      
            if (isValid == true && subtotal <= 0)
            {                
                System.out.println("Error! Number must be greater than 0. Try entering a greater number.");
                isValid = false;
            }
            else if (subtotal >= 10000)
            {
                System.out.println("Error! Number must be less than 10000. Try entering a number with a lower value.");
                isValid = false;
            }    
        }     //  end while()
        return subtotal;
    }        
}