Scanner will fail to read integer for a specific data. Please see the variosu inputs.
code used:-
import java.io.*;
import java.util.*;
/*
  This should test the various inputs of integers and longs.

*/

public class Test {
    public static void main(String[] args) {
        try {
            System.out.println(" Enter Integer ");
            Scanner scanner = Scanner.create(System.in);
            int inte = scanner.nextInt();
            System.out.println(" Enter Long ");
            long lng = scanner.nextLong();
        } catch(Exception exp) {
            exp.printStackTrace();
        }
    }
}

output screen :-
vishalb:/home/vv145429/tiger/src/scanning/Assertion2 44 % java Test
 Enter Integer
4578
 Enter Long
012345
vishalb:/home/vv145429/tiger/src/scanning/Assertion2 45 % java Test
 Enter Integer
04578
java.util.InputMismatchException
        at java.util.Scanner.throwFor(Scanner.java:761)
        at java.util.Scanner.next(Scanner.java:1235)
        at java.util.Scanner.nextInt(Scanner.java:1623)
        at Test.main(Test.java:14)
vishalb:/home/vv145429/tiger/src/scanning/Assertion2 46 % java Test
 Enter Integer
01234
 Enter Long
0012345
vishalb:/home/vv145429/tiger/src/scanning/Assertion2 47 % java Test
 Enter Integer
05555
 Enter Long
-123456
vishalb:/home/vv145429/tiger/src/scanning/Assertion2 48 % java Test
 Enter Integer
005555
 Enter Long
-0123456

If u look at the data 01234 <04578 <05555. it fails at 04578 and accepts if u don;t use 0 and it will accept 0 for other two numbers.