java - How is timezone EST different from EST5EDT? -

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• joda time datetimezone 2 answers

how different est est5edt ? isn't est take account dst?

i wrote small java snippet figure out difference , output says est5edt takes in account dst while est not

simpledateformat dateformat = new simpledateformat("yyyy-mmm-dd hh:mm:ss.sss");  dateformat.settimezone(timezone.gettimezone("est5edt"));  system.out.println("est5edt" +dateformat.format(new date()));     /* prints est5edt2013-apr-05 02:24:16.471 */     dateformat = new simpledateformat("yyyy-mmm-dd hh:mm:ss.sss");  dateformat.settimezone(timezone.gettimezone("est"));  system.out.println("est "+dateformat.format(new date()));    /*prints est 2013-apr-05 01:24:16.472 */ 

but below snippet produced shocking output

system.out.println("est5edt offset "+timezone.gettimezone("est5edt").getrawoffset()/(60*60*1000)); /* prints 5 instead of 4 (dst) */ 

could please explain happening here ? why getrawoffset returning 5 instead of 4 ? how timezone offset dst?

isn't est take account dst?

no. definition est "eastern standard time" or utc-5:00.

edt "eastern daylight time" or utc-4:00.

it's bit confusing, because example, new york switches between est , edt, , seattle switches between pst , pdt.

sometimes people incorrectly "i'll call 1pm est" when mean say, " i'll call 1pm eastern time" takes account whether or not it's daylight savings.

this wikipage has little more information.

why getrawoffset returning 5 instead of 4

timezone.getrawoffset returns number of milliseconds standard time, 5 * (60 * 60 * 1000)

since utc offset changes based of day of year (to account dst), you'll need use getoffset, , supply date want use.