# Java Scanner issues

by jjc
Tags: java, scanner
 P: 21 I am having some trouble with the Java Scanner to read input from the keyboard. I am trying to keep my input cleaned up and secure, so I am checking for the right type and value, and clearing the input buffer if it isn't. I also restart the prompt loop if it isn't right, so they can try again. I am using the .nextLine() method to clear the input buffer. The problem that I am seeing is that I sometimes don't get a repeated prompt until I enter in a second input. Things seem to work fine without the nextLine() calls, but then I always feel like I am leaving a dangling possible problem. I was also trying to use combinations of while(!talkToMe.hasNextInt()) loops to try and get away from my Flag system shown below, but it didn't quite seem to work so I stuck with the flags. I have read through the Java API documentation but that didn't seem to help, and I have done other searches for explanations of the Scanner object. It just feels like I am missing some key element of how the Scanner class is working. Is it an interrupt driven thing? A sit-and-wait-for-the-input thing? These questions might be the root of it; perhaps by executing .nextLine() it is actually waiting instead of going to the next statement. Thanks for the help, JJC Here is a code chunk at the moment: private int createPin1 (String prompt) { int pin1=-1; boolean flag = false; while (!flag){ talkToMe.nextLine(); //not sure if this line is going to mess things up. do { System.out.print(""+ prompt); //Asking for pin number. }while (!talkToMe.hasNextInt()); pin1 = talkToMe.nextInt(); talkToMe.nextLine(); //not sure if this might mess things up again. if (pin1 <= 0){ System.out.println("Try again; please enter an integer > 0."); // System.out.println(""+ prompt); }else flag = true; } return pin1; }