I am assuming you are using java 7, thus you get a compiler warning, when you don't close the resource you should close your scanner usually in a finally block.
Scanner scanner = null;
try {
scanner = new Scanner(System.in);
//rest of the code
}
finally {
if(scanner!=null)
scanner.close();
}
Or even better: use the new Try with resource statement:
try(Scanner scanner = new Scanner(System.in)){
//rest of your code
}