Java SimpleDateFormat timezone parsing
I'm curious how Java's SimpleDateFormat decides when to increment/decrement the passed in time based on the timezone it's set to.
Let's say I have a date 06/04/2013. I then set the timezone to one far away from me(I'm in GMT-5). Let's say I use GMT+8.
I call
SimpleDateFormat df = new SimpleDateFormat( "M/d/yy" );
df.setTimeZone( TimeZone.getTimeZone( "GMT+8" ) );
df.parse( endDate ) // this returns 06/**03**/2013 //endDate is just a String
It returns 06/03/2013. Why does it decrement it?
Edit: Basically I'm asking what is the reference point that Java uses to knock back my date to 6/3 if I set it to GMT+8. There's some logic that says hey I'm not on this current timezone so let's change it. But since I'm passing in a String I don't see where it could be.
I assume by default if I don't provide a Timezone in the string it will default to GMT.
You're in GMT-5, and you're parsing a string representing a moment in the GMT+8 time zone.
So, the date 06/04/2013 is in fact 06/04/2013 00:00 GMT+8 . To get the date at GMT, you have to subtract 8 hours: 06/03/2013 16:00 GMT . And to get the date at GMT-5, you have to subtract another 5 hours: 06/03/2013 11:00 GMT-5 .
All these strings are different representations of the same moment.
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