Add java.time support to EJB Timer

[thatsIch]

EJB provides a subsection for scheduler and timers.

To create a timer you can inject a TimerService like

@Inject
TimerService timerService;

The TimerService provides methods to create single-action timer amonst other ways either by TimerService#createTimer(Date, Serializable) or TimerService#createSingleActionTimer(Date, TimerConfig but none where you can with a java.time parameter like LocalDateTime.

Currently, it is required to convert LocalDateTime or other members of java.time to Date by using converters like

public Date convertToDateViaSqlTimestamp(LocalDateTime dateToConvert) {
    return java.sql.Timestamp.valueOf(dateToConvert);
}

or through java.time.Instant

Date convertToDateViaInstant(LocalDateTime dateToConvert) {
    return java.util.Date
      .from(dateToConvert.atZone(ZoneId.systemDefault())
      .toInstant());
}

It was telegraphed that the alignment from JakartaEE/JavaEE to Java 8+ was an important step and adding support for java.time is part of this.

I suggest adding methods

public Timer createSingleActionTimer(LocalDateTime, TimerConfig timerConfig) throws IllegalArgumentException, IllegalStateException, EJBException

and sibling methods to add java.time support to ejb timers.