Java: Try to Understand Getting Inputs from Users Using Scanner -

i have programs , few questions regarding how .next(), .nextint(), .hasnext() , .hasnextint() of scanner class work. thank in advance of :)

import java.util.scanner;  public class test {      public static void main (string[] args) {     scanner console = new scanner(system.in);     int age;     system.out.print("please enter age: ");     while (!console.hasnextint()) {             system.out.print("please re-enter age: ");             console.next();         }     age = console.nextint();     system.out.println("your age "+age);     }   } 

1/ when !console.hasnextint() executed first time, why ask input?

i thought @ first console empty, !console.hasnextint() true (empty not int), should go directly "please enter age: " "please re-enter age: " thought seems wrong.

here, user needs enter before "please re-enter age: " printed.

2/ data type of console.next() string (i tried making int s = console.next(); , gave error), why isn't infinite loop?

3/ instance, when comes console.next();, input 21. why age have value of 21? thought because of console.hasnextint(), need enter number, , new number value of age.

hasnextint() waits input string , tells if can converted int. in mind, let's go on questions:

when !console.hasnextint() executed first time, why ask input?

because blocks until there's input console.

the data type of console.next() string (i tried making int s = console.next(); , gave error), why isn't infinite loop?

because hasnextint() returns true when input can converted int, example "21".

for instance, when comes console.next();, input 21. why age have value of 21? thought because of console.hasnextint(), need enter number, , new number value of age.

calling next() doesn't wait new input, swallows input tested hasnextint() scanner can move on next one. have been first statement in loop, same effect.