Scanning odd timezones via java.time.* (Java8)

java8-time.groovy

// inspired by https://kousenit.org/2016/07/16/fun-with-time-zones-in-java-8/
import java.time.*
import java.time.format.*

final boolean shouldIncludeHourOffsets = false
LocalDateTime now = LocalDateTime.now()
List<ZonedDateTime> zdts = ZoneId.availableZoneIds
    .collect { now.atZone(ZoneId.of(it)) }
    .findAll { shouldIncludeHourOffsets || it.offset.totalSeconds % (60*60) != 0 }
    .sort { it.offset.totalSeconds }

ZonedDateTime current = now.atZone(ZoneId.systemDefault())
println "current time = ${current}"
printf "%10s %20s %13s%n", 'Offset', 'ZoneId', 'Time'
final dtfFormat = DateTimeFormatter.ofLocalizedTime(FormatStyle.SHORT)
zdts.each {
    ZonedDateTime zdt = current.withZoneSameInstant(it.zone)
    printf "%10s %25s %10s%n", zdt.offset, it.zone, zdt.format(dtfFormat)
}

println "#zones:\t${zdts.size()}" // 26 if filtered; else 589
// includes 5 zones off by 15/45 minutes; other 21 are 30 min offsets