The (real life) problemFollowing my question on SO, I found out that printing a Java Date() in a custom format is quite tedious:final Date date = new Date();final String ISO_FORMAT = yyyy-MM-dd'T'HH:mm:ss.SSS zzz;final SimpleDateFormat sdf = new SimpleDateFormat(ISO_FORMAT);final TimeZone utc = TimeZone.getTimeZone(UTC);sdf.setTimeZone(utc);System.out.println(sdf.format(date));I was looking for a one-liner without object initialization:System.out.println(magic(date, yyyy-MM-dd'T'HH:mm:ss.SSS zzz, UTC));My SolutionPrettyDate class, which formats Date() objects using TimeZones and Formats given  as strings, sans any external object creation. There are some convenience methods for popular timezone\format combinations.Alternatives to Consider (please comment on these, too!)Extending Date() with better toString()Using non-static methods: Initializing PrettyDate with a Format and a TimeZone, and feeding it with Date objects to get a string representationUsage// The problem - not UTCDate.toString()                      Tue Jul 03 14:54:24 IDT 2012// ISO format, nowPrettyDate.now()        2012-07-03T11:54:24.256 UTC// ISO format, specific datePrettyDate.toString(new Date())         2012-07-03T11:54:24.256 UTC// Legacy format, specific datePrettyDate.toLegacyString(new Date())   Tue Jul 03 11:54:24 UTC 2012// ISO, specific date and time zonePrettyDate.toString(moonLandingDate, yyyy-MM-dd hh:mm:ss zzz, CST) 1969-08-20 03:17:40 CDT// Specific format and datePrettyDate.toString(moonLandingDate, yyyy-MM-dd)1969-08-20// ISO, specific datePrettyDate.toString(moonLandingDate)1969-08-20T20:17:40.234 UTC// Legacy, specific datePrettyDate.toLegacyString(moonLandingDate)Wed Aug 20 08:17:40 UTC 1969Codeimport java.text.SimpleDateFormat;import java.util.Date;import java.util.TimeZone;/** * Formats dates to sortable UTC strings in compliance with ISO-8601. *  * @author Adam Matan <adam@matan.name> * @see https://stackoverflow.com/questions/11294307/convert-java-date-to-utc-string/11294308 */public class PrettyDate {    public static String ISO_FORMAT = yyyy-MM-dd'T'HH:mm:ss.SSS zzz;    public static String LEGACY_FORMAT = EEE MMM dd hh:mm:ss zzz yyyy;    private static final TimeZone utc = TimeZone.getTimeZone(UTC);    private static final SimpleDateFormat legacyFormatter = new SimpleDateFormat(LEGACY_FORMAT);    private static final SimpleDateFormat isoFormatter = new SimpleDateFormat(ISO_FORMAT);    static {        legacyFormatter.setTimeZone(utc);        isoFormatter.setTimeZone(utc);    }    /**     * Formats the current time in a sortable ISO-8601 UTC format.     *      * @return Current time in ISO-8601 format, e.g. :     *         2012-07-03T07:59:09.206 UTC     */    public static String now() {        return PrettyDate.toString(new Date());    }    /**     * Formats a given date in a sortable ISO-8601 UTC format.     *      * <pre>     * <code>     * final Calendar moonLandingCalendar = Calendar.getInstance(TimeZone.getTimeZone(UTC));     * moonLandingCalendar.set(1969, 7, 20, 20, 18, 0);     * final Date moonLandingDate = moonLandingCalendar.getTime();     * System.out.println(UTCDate.toString moon:        + PrettyDate.toString(moonLandingDate));     * >>> UTCDate.toString moon:       1969-08-20T20:18:00.209 UTC     * </code>     * </pre>     *      * @param date     *            Valid Date object.     * @return The given date in ISO-8601 format.     *      */    public static String toString(final Date date) {        return isoFormatter.format(date);    }    /**     * Formats a given date in the standard Java Date.toString(), using UTC     * instead of locale time zone.     *      * <pre>     * <code>     * System.out.println(UTCDate.toLegacyString(new Date()));     * >>> Tue Jul 03 07:33:57 UTC 2012     * </code>     * </pre>     *      * @param date     *            Valid Date object.     * @return The given date in Legacy Date.toString() format, e.g.     *         Tue Jul 03 09:34:17 IDT 2012     */    public static String toLegacyString(final Date date) {        return legacyFormatter.format(date);    }    /**     * Formats a date in any given format at UTC.     *      * <pre>     * <code>     * final Calendar moonLandingCalendar = Calendar.getInstance(TimeZone.getTimeZone(UTC));     * moonLandingCalendar.set(1969, 7, 20, 20, 17, 40);     * final Date moonLandingDate = moonLandingCalendar.getTime();     * PrettyDate.toString(moonLandingDate, yyyy-MM-dd)     * >>> 1969-08-20     * </code>     * </pre>     *      *      * @param date     *            Valid Date object.     * @param format     *            String representation of the format, e.g. yyyy-MM-dd     * @return The given date formatted in the given format.     */    public static String toString(final Date date, final String format) {        return toString(date, format, UTC);    }    /**     * Formats a date at any given format String, at any given Timezone String.     *      *      * @param date     *            Valid Date object     * @param format     *            String representation of the format, e.g. yyyy-MM-dd HH:mm     * @param timezone     *            String representation of the time zone, e.g. CST     * @return The formatted date in the given time zone.     */    public static String toString(final Date date, final String format, final String timezone) {        final TimeZone tz = TimeZone.getTimeZone(timezone);        final SimpleDateFormat formatter = new SimpleDateFormat(format);        formatter.setTimeZone(tz);        return formatter.format(date);    }}
Java Date formatter
java;strings;datetime
The thing about Date is that there are so many different time zones, so many different standard ways of representing the date and even, in some places, completely different calendar systems. As a result, Sun designed Date to not make any assumptions about anything and let application developers write whatever implementation best suited them.So, if you find your implementation for PrettyDate works well for you, that's ok. My only comment about that is that heavy use of static methods smells of procedural, rather than object oriented thinking, and that's not a good thing. Embrace the objects.