Seconds to hr/min/sec conversion error

Question

I typed up this simple sample program and for some reason when I execute it, I get one second less than the actual value. For instance, I typed in 9999 and got 2 hours, 46 minutes, 38 seconds. It should be 39. What did I do wrong? Here's the code:
import cs1.Keyboard;
public class Tim
public static void main (String[] args)
final int CONVERSION = 60;
final double HOUR_CONVERSION = 3600.0;
int hour1, minute1, seconds1;
double seconds, minute, hour;
System.out.print ("How many seconds have you been sleeping? ");
seconds = Keyboard.readInt();
hour = seconds / HOUR_CONVERSION;
minute = (hour - (int)hour) * CONVERSION;
seconds = (int) ((minute - (int)minute) * CONVERSION);
hour1 = (int) hour;
minute1 = (int) minute;
seconds1 = (int) seconds;
System.out.print ("You slept for " + hour1 + " hours, "
+ minute1 + " minutes, and "
+ seconds1 + " seconds.");

Answer 1

My suspicion is a rounding error. When you do the
last conversion to seconds, I supect you are getting
something like 38.99999999. and just in case it wasn't clear (no offense, EE), converting fp types to int types in Java always truncates, so (int)38.99999999999 ends up as 38.