I want to print multiple lines of a while loop in 1 gui dialog box.

This is the code I have currently

```
package Tempconv1;
import javax.swing.JOptionPane;
public class TimesTables 
{

    public static void main(String[] args)
    {
        int num1 = 0, counter = 0, total = 0; //Declaring Variables
        String str; //String for ShowInputDialog

        str = JOptionPane.showInputDialog("Insert a number");  //Asks user to input number
        num1 = Integer.parseInt(str); 

            //Calculating number inputs
            while (counter <12)
            {
                counter = counter + 1;
                total = counter * num1;
                String multimsg = ("The calculation is " + num1 + " x " + counter + "=" + total);
                JOptionPane.showMessageDialog(null, multimsg);
            }
            JOptionPane.showMessageDialog(null, "All Done");
    }

}

```

It works but prints out "The calculation is 5x1 = 5" and then opens a new message box to show "The calculation is 5x2 = 10".
I want it to print out

The Calculation is 5x1 = 5
The Calculation is 5x2 = 10
etc

All inside 1 textbox