eg. If you declare a variable named total and make it = 0.
Each time going through a loop with this line of code;

total = total + price;

the total becomes equal to whatever value total has...

Sorry while(true) I meant there, not while(1).

You could
do away with the Do-while and instead use an infinite loop.

while(1)
{
print out menu, get choice

switch(choice)
{
Ask to quit in here, scan input and then break out of...

You can convert the Jar to an Exe, and run it then. Just google "Jar to Exe."
At least that's how I how I did it, perhaps there's an easier way.