Java by API/java.util/TimeZone

TimeZone: getAvailableIDs()

 
import java.util.Arrays;
import java.util.TimeZone;
public class Main {
    public static void main(String[] args) {
        String[] allTimeZones = TimeZone.getAvailableIDs();
        
        Arrays.sort(allTimeZones);
        for (String timezone : allTimeZones) {
            System.out.println(timezone);
        }
    }
}

TimeZone: getDefault()

 

import java.util.Calendar;
import java.util.GregorianCalendar;
import java.util.TimeZone;
public class Main {
  public static void main(String[] argv) throws Exception {
    // Get the current time in Hong Kong
    Calendar cal = new GregorianCalendar(TimeZone.getTimeZone("Hongkong"));
    int hour12 = cal.get(Calendar.HOUR); // 0..11
    int minutes = cal.get(Calendar.MINUTE); // 0..59
    int seconds = cal.get(Calendar.SECOND); // 0..59
    boolean am = cal.get(Calendar.AM_PM) == Calendar.AM;
    // Get the current hour-of-day at GMT
    cal.setTimeZone(TimeZone.getTimeZone("GMT"));
    int hour24 = cal.get(Calendar.HOUR_OF_DAY); // 0..23
    // Get the current local hour-of-day
    cal.setTimeZone(TimeZone.getDefault());
    hour24 = cal.get(Calendar.HOUR_OF_DAY); // 0..23
  }
}

TimeZone: getDisplayName()

 
import java.util.Calendar;
import java.util.TimeZone;
public class Main {
  public static void main(String[] args) {
    Calendar now = Calendar.getInstance();
    TimeZone timeZone = now.getTimeZone();
    System.out.println("Current TimeZone is : " + timeZone.getDisplayName());
  }
}

TimeZone: getTimeZone(String ID)

     
import java.util.GregorianCalendar;
import java.util.Locale;
import java.util.TimeZone;
public class Main {
  public static void main(String[] a) {
    GregorianCalendar calendar = new GregorianCalendar(TimeZone.getTimeZone("America/Chicago"),
        Locale.US);
    System.out.println(calendar);
  }
}