Java Utililty Methods TimeUnit Usage

String formattedTime = null;
if (timeleft <= 0)
    formattedTime = String.format("%02d:%02d:%02d", 0, 0, 0);
else {
    final long hours = TimeUnit.MILLISECONDS.toHours(timeleft);
    final long minutes = TimeUnit.MILLISECONDS.toMinutes(timeleft - TimeUnit.HOURS.toMillis(hours));
    final long seconds = TimeUnit.MILLISECONDS
            .toSeconds(timeleft - TimeUnit.HOURS.toMillis(hours) - TimeUnit.MINUTES.toMillis(minutes));
...

TimeUnit timeunit = TimeUnit.MILLISECONDS;
long hours = timeunit.toHours(timeInMillis);
long minutes = timeunit.toMinutes(timeInMillis) - TimeUnit.HOURS.toMinutes(hours);
long seconds = timeunit.toSeconds(timeInMillis) - TimeUnit.HOURS.toSeconds(hours)
        - TimeUnit.MINUTES.toSeconds(minutes);
return ((hours < 10) ? "0" + hours : hours) + ":" + ((minutes < 10) ? "0" + minutes : minutes) + ":"
        + ((seconds < 10) ? "0" + seconds : seconds);

final StringBuilder sb = new StringBuilder();
long months = TimeUnit.MILLISECONDS.toDays(duration);
if (months >= 30) {
    months = months / 30;
    duration -= TimeUnit.DAYS.toMillis(months * 30);
} else {
    months = 0;
final long years = months / 12;
if (years > 0) {
    months -= Math.floor(years * 12);
    duration -= TimeUnit.DAYS.toMillis(years * 365);
final long days = TimeUnit.MILLISECONDS.toDays(duration);
duration -= TimeUnit.DAYS.toMillis(days);
final long hours = TimeUnit.MILLISECONDS.toHours(duration);
duration -= TimeUnit.HOURS.toMillis(hours);
final long minutes = TimeUnit.MILLISECONDS.toMinutes(duration);
duration -= TimeUnit.MINUTES.toMillis(minutes);
final long seconds = TimeUnit.MILLISECONDS.toSeconds(duration);
if (years > 0) {
    sb.append(" ").append(years);
    sb.append(" ").append(years == 1 ? "year" : "years");
if (months > 0) {
    sb.append(" ").append(months);
    sb.append(" ").append(months == 1 ? "month" : "months");
if (days > 0) {
    sb.append(" ").append(days);
    sb.append(" ").append(days == 1 ? "day" : "days");
if (hours > 0) {
    sb.append(" ").append(hours);
    sb.append(" ").append(hours == 1 ? "hour" : "hours");
if (minutes > 0) {
    sb.append(" ").append(minutes);
    sb.append(" ").append(minutes == 1 ? "minute" : "minutes");
if (seconds > 0) {
    sb.append(" ").append(seconds);
    sb.append(" ").append(seconds == 1 ? "second" : "seconds");
return sb.toString().trim();

return getInsertionEndIndex(list, key, list instanceof RandomAccess);

long pollIntervalInSeconds = (int) TimeUnit.MILLISECONDS.toSeconds(Long.parseLong(pollInterval));
return Long.toString(pollIntervalInSeconds);

long lastSlotDate = firstSlotDate;
if (occurrences > 1) {
    int selectedDay = firstSlotDay;
    int intervalFromFirstDay = 0;
    for (int i = 1; i <= (occurrences - 1); i++) {
        int interval = getNextInterval(selectedDay, selectedDays, periodicity);
        intervalFromFirstDay += interval;
        selectedDay = (selectedDay + interval) % 7;
...

Long nextValue = null;
boolean done = false;
while (done == false) {
    try {
        nextValue = queue.poll();
        while (nextValue == null) {
            Thread.sleep(Q_POLL_SLEEP_DURATION_);
            nextValue = queue.poll();
...

Properties props = new Properties();
props.setProperty("connect.mail.user", toAddress);
props.setProperty("connect.mail.pass", toAddress);
props.setProperty("connect.max.msgs.in.batch", Integer.toString(MAX_NUM_MSGS_IN_BATCH));
props.setProperty("connect.delete.unhandled.msgs", "false");
props.setProperty("connect.mail.session.debug", "true");
props.setProperty("mail.smtp.host", "localhost");
props.setProperty("mail.smtp.auth", "TRUE");
...

return (int) (milliseconds % HOUR / MINUTE);

return (int) TimeUnit.MILLISECONDS.toMinutes(end_date.getTime() - begin_date.getTime());