The following piece of code should return true.

> LocalDateTime ldt = LocalDateTime.parse("2017-01-01T00:00:00");
> ZonedDateTime dt1 = ZonedDateTime.of(ldt, ZoneId.of("GMT+10"));
> ZonedDateTime dt2 = ZonedDateTime.of(ldt, ZoneId.of("UTC+10"));
>
> dt1.equals(dt2) returns true as expected, but with:
>
> GregorianCalendar gc1 = GregorianCalendar.from(dt1);
> GregorianCalendar gc2 = GregorianCalendar.from(dt2);
>
> gc1.equals(gc2) returns false.