exception in thread "main" java.lang.numberformatexception: for input string: ""
int number = 0; // or any application default value
try {
number = Integer.parseInt(input);
} catch (NumberFormatException nfe) {
// do whatever you need to do if you get an invalid number
// you can put the try catch in a loop and keep asking for a
// value until you don't get a valid one
// If you want to use the default value in case of an
// invalid number you can do nothing in here
}