Need help with basic Java programming

Question

I'm having a little bit of trouble with my code. For the sake of argument, I've removed the code I'm having trouble with, because I know it was inaccurate. I'm trying to create a loop so that this program will keep going through and through until the user enters an invalid variable. I thought the default after the case statements was supposed to make the system exit and output my message. Those two problems, the loop and the default, are what I'm really having problems with. My code is posted below.
import javax.swing.JOptionPane;
import java.util.Locale;
import java.text.NumberFormat;
public class Retail
public static void main(String args[])
String firstNum;
String secondNum;
String result;
int prodNum;      //first number to input
double quantity; //second number to input
double total = 0.0;     //total of Prod * Quantity Sold for all items
// To use American Dollar
NumberFormat moneyFormat = NumberFormat.getCurrencyInstance( Locale.US );
// first number entered as string
firstNum = JOptionPane.showInputDialog( "Enter product number 1-5" );
// second number entered as string
secondNum = JOptionPane.showInputDialog( " Enter quantity of items sold" );
// convert values to type double or int from type string
prodNum = Integer.parseInt( firstNum );
quantity = Double.parseDouble( secondNum);
result="";
if ( prodNum >=1 && prodNum <=5 ) {
switch (prodNum)
case 1: // 1st product
total = 2.98 * quantity;
break;
case 2: // 2nd product
total = 4.50 * quantity;
break;
case 3: // 3rd product
total = 9.98 * quantity;
break;
case 4: //4th product
total = 4.49 * quantity;
break;
case 5:
total = 6.87 * quantity;
break;
default: JOptionPane.showMessageDialog( null, "Wrong product number entered" );
JOptionPane.showMessageDialog( null, moneyFormat.format(total), "Total Price of Items Purchased", JOptionPane.INFORMATION_MESSAGE );
System.exit(0);
***I know I need to put something in the user input message to state that any value other than 1-5 entered will cause the program to skip to the output, I'll put that in later.***

Answer 1

When you post code, please use [code] and [/code] tags as described in Formatting Help on the message entry page. It makes it much easier to read and prevents accidental markup from array indices like [i].