get timezone abbreviation in android

Question

I'm trying to get Timezone abbreviation for the given Timezone. Here is my code.

TimeZone  tz=TimeZone.getTimeZone("GMT+05:30");
Log.e("given time zone >>",tz.getDisplayName(false,TimeZone.SHORT));

But I get in log as GMT+05:30 only, I like to get IST (abbreviation). What I have done wrong?