In this program converting one time unit value to hour, minute and second. Generally such type of questions asked in interview to check programming logic.

See Also: Java Program : How to convert units?

import java.util.Scanner;

public class TimeConversion {
	static int SECOND = 60*60;
	static int MINUTE = 60;
	static int HOUR = 1;

		public static void main(String[] args) { 

			System.out.println("Please enter :\nh for hour\nm for minute \ns for second");
			Scanner in = new Scanner(System.in);
			System.out.println("Convert from:");
			String fromUnit = in.nextLine();
			System.out.println("Value:");
			int val = in.nextInt();
			String convertedTime = convertTime(fromUnit,val);
			System.out.println("Converted Time :"+convertedTime);
			} 

		private static String convertTime(String unit, int value)
		{
			int h=0,m=0,s=0,seconds=0;
			//Convert to seconds
			switch(unit)
			{
			case "h": seconds=value*SECOND;
			break;
			case "m": seconds=value*MINUTE;
			break;
			case "s": seconds=value;
			break;
			}

			h=seconds/SECOND;
			value=seconds%SECOND;

			m=value/MINUTE;
			value=value%MINUTE;

			s=value/SECOND;

			return h+" Hour "+m+" Minute "+s+" Second";
		}
	}

Output

Please enter :
h for hour
m for minute 
s for second
Convert from:
m
Value:
60
Converted Time :1 Hour 0 Minute 0 Second