Use String.
Use String.format to format the date, as opposed to toString with uses SimpleDateFormat
Make sure the hashCode is the same as Date for the (questionable) choice to make them equal.
Make sure the hashCode is the same as Date for the (questionable) choice to make them equal. this is the same as what java does (and only sane thing): http://grepcode.com/file/repository.grepcode.com/java/root/jdk/openjdk/6-b14/java/util/Date.java#989
Use SimpleDateFormat to print the string
A value class wrapper for milliseconds since the epoch