Java – Scanner

InputStream in read user input from terminal bytes by bytes. We can use the Scanner class to read the whole string.

public static void main(String[] args) {
		
  Scanner in = new Scanner(System.in);
  System.out.print("Enter your username: ");
  String username = in.nextLine();
  System.out.println("Username : " + username);

}		

To read integer, try enter any single digit from 0 – 9,

public static void main(String[] args) {
		
  Scanner in = new Scanner(System.in);
  System.out.print("Enter extension line 0 - 9: ");
  int line = in.nextInt();
  System.out.printf("You've select line %d \n", line);
}		

What if you allow to enter more digit separated by space?

Scanner in = new Scanner(System.in);
   System.out.print("Enter extension line 0 - 9: ");
   while (in.hasNextInt()) {
     System.out.printf("You've select line %d \n", in.nextInt());
   }
 }