This means it is impossible for one of the statements in your program to be reached. Usually, this is because you have written some code in between method definitions.
There are several ways that these errors can occur in switch blocks:
int a = (int)(Math.random()*2); switch(a) { case 0: System.out.println("Zero!"); break; System.out.println("oops!"); This statement is not inside a case case 1: System.out.println("One!"); break; case 2: return ("Sausages!"); The return here means the break; is never reached. break; Store the return in a variable and return outside the switch. default: System.out.println("Another thing!"); break;