List time zones with UTC and DST offsets

java_timezones.groovy

new File("/tmp/java_timezones.txt").withWriter { out ->
    TimeZone.getAvailableIDs().each{ timezoneId -> 
        timezone = TimeZone.getTimeZone(timezoneId) 
        def items = [timezone.getID(),
        (int)(timezone.getRawOffset()/1000),
        (int)(timezone.getDSTSavings()/1000)]    
        out.print sprintf("%6d %32s %6d\n",items[1],items[0],items[2])
    }
}

rails_timezones.rb

require 'bundler/setup'
require 'active_support/time_with_zone'
File.open('/tmp/ruby_timezones.txt','w'){|out|
  out.puts ActiveSupport::TimeZone.all.map{|t| t.tzinfo }.map{|tz|
    sprintf("%6d %32s %6d",tz.current_period.utc_offset, tz.name, tz.current_period.std_offset)
  }
}

tzinfo_timezones.rb

offsets = TZInfo::Timezone.all.map{|tz| [tz.current_period.utc_offset/3600.0,tz.name] }.sort_by{|o| o[0] }