Java zoneid Class | Java Tutorial

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Java 8 Date Time Classes

ZoneId class Usage

ZoneId represents time-zone id , such as Asia/Kolkata, Europe/Paris,America/New_York , etc., Each country has time-zone, some countries have multiple time-zones and these time-zones are adjusted based on DayLightSaving settings.

Creating a ZoneId Object. In order to create ZoneId object, you should know the time-zone id, User can use systemDefault method or getAvailableZoneIds method to get zone id.

Using static methods

systemDefault

Get system's time-zone.

      				ZoneId zid = ZoneId.systemDefault();
      				System.out.println(zid)
      				Asia/Kolkata

getAvailableZoneIds

gets all available time-zones as Set object. User can pick one from these list of time-zones

		
		Set<String> zids = ZoneId.getAvailableIds();
		
		[Asia/Aden, America/Cuiaba, Etc/GMT+9, Etc/GMT+8, Africa/Nairobi, 
		America/Marigot, Asia/Aqtau, Pacific/Kwajalein, America/El_Salvador, 
		Asia/Pontianak, Africa/Cairo, Pacific/Pago_Pago, Africa/Mbabane, 
		Asia/Kuching, Pacific/Honolulu, Pacific/Rarotonga, America/Guatemala, 
		Australia/Hobart, Europe/London, America/Belize, America/Panama, 
		/Chungking, America/Managua, America/Indiana/Petersburg, Asia/Yerevan, 
		Europe/Brussels, GMT, Europe/Warsaw, America/Chicago, Asia/Kashgar, 
		Chile/Continental, Pacific/Yap, CET, Etc/GMT-1, Etc/GMT-0, Europe/Jersey, 
		America/Tegucigalpa, Etc/GMT-5, Europe/Istanbul, America/Eirunepe, Etc/GMT-4, 
		America/Miquelon, Etc/GMT-3, Eur ... Asia/Irkutsk, America/Shiprock, 
		America/Winnipeg, Europe/Vatican, Asia/Amman, Etc/UTC, SystemV/AST4ADT, 
		Asia/Tokyo, America/Toronto, Asia/Singapore, Australia/Lindeman, 
		America/Los_Angeles, SystemV/EST5EDT, Pacific/Majuro, America/Argentina/Buenos_Aires, 
		Europe/Nicosia, Pacific/Guadalcanal, Europe/Athens, US/Pacific, Europe/Monaco]

Display Region Specific Time-zone Ids

use static method getAvailableZoneIds method, split each time-zone id using forward slash, check for region, display only those region specific time-zone ids.

        Set<String> zids = ZoneId.getAvailabelIds();
        
	for (String zid : zids)
   	 {   
   	 	String []t = zid.split("/"); 
	   	 if(t[0].compareTo("Asia")==0)
        	 System.out.println(zid);
   	}

	//Output
	Asia/Tokyo
	Asia/Singapore
	.....

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