How do i make the user input loop until the input is valid?

Question

Scanner input = new Scanner(System.in);
String jobselect;
int x = 0;
do{
jobselect = input.next();
switch(jobselect){
case "pld":
Paladin pld = new Paladin();
pld.sheet();
x += 1;
break;
case "gla":
Gladiator gla = new Gladiator();
gla.sheet();
x += 1;
break;
default:
x += 0;
break;
}
} while (x < 1);

Answer 1

Why don't you add a Yes/No condition where the if the user may want to add a next input, then he can, else the do-while loop terminates.

Answer 2

I attempted it with the x+= 1. Just throws exceptions