How do you parse, using using the ThreeTen library (I can't use java 8) a string of the following format:
15 Aug 2014
forcing this to become a ZonedDateTime
meaning 15 August 2014 in UTC timezone at midnight?
I assume you mean 2014, not 2010. If so then following code can help you:
LocalDate date =
LocalDate.parse(
"15 Aug 2014",
DateTimeFormatter.ofPattern("dd MMM uuuu", Locale.ENGLISH));
ZonedDateTime zdt = date.atStartOfDay(ZoneOffset.UTC);
System.out.print(zdt);
// output: 2014-08-15T00:00Z
Another more clunky way would be to use a specialized DateTimeFormatterBuilder
using the method parseDefaulting() for the missing time and offset (not tested).