JDK 1.5.0_01

This is more of a suprising difference between 3.6
and 4.0 than anything else.

when using the following code

//This is a program to determine whether or not a
user entered year is a leap year on the Gregorian
Calender
package GPP3;

import cs1.Keyboard;
public class GPP3_03 {
    
    public static void main(String[] args) {
        final int
LEAP_NUM=4,LEAPCK1=100,LEAPCK2=400,GREGCK=1583;
        int year, id=0;
        
        System.out.print("Please enter the Year to
be checked: ");
        year=Keyboard.readInt();
        
        while (year != 0) {
            if (year%LEAP_NUM==0)
                id=1;
            if (year%LEAPCK1==0){
                id=0;
                if (year%LEAPCK2==0)
                    id=1;
            }
            if (year<GREGCK)
                id=3;
            
            if (id==1)
                System.out.println("The year is a
leap year");
            else
                if (id==0)
                    System.out.println("The year
is not a leap year");
                else
                    System.out.println("The
Gregorian calender was not created by that time");
            
            System.out.print("Please enter the
Year to be checked (0 to exit): ");
            year=Keyboard.readInt();
            
        }
    }
    
}

along with the cs1.keyboard class found at 

http://duke.csc.villanova.edu/jss/downloads/Keyboard.java

The IDE (3.6) used to run normally (executing the
code and prompting the user for int input), But
now it gets to the input point and give the error

Error reading int data, MIN_VALUE value returned.

Only Netbeans 4.0 does this, regardless of JDK
version, I have tried JCreator and  the code
executes normally

Nothing else has been changed from when the code
ran normally to when it failed except for
upgrading to Netbeans 4.0