Software Dev – Page 3 of 11

KosherJava Zmanim Library Package Name and Build Process Update

The KosherJava zmanim library originally went live in 2004. There was an existing C/C++ zmanim project by Ken Bloom hosted on SourceForge (that was at the time the equivalent of what GitHub is today). The Java package structure name net.sourceforge.zmanim was based on the one used by Ken’s project (despite not being hosted there), and remained that way for 16 years.
On August 3, 2020, Eli Julian modernized the library’s build process from the previously used Ant, to Maven & Gradle. This change simplified the workflow for many developers using the zmanim API. As part of the change, the package name was updated to com.kosherjava.zmanim. The KosherJava zmanim Maven / Gradle artifacts are available at the KosherJava zmanim Maven Central page. A direct Jar download is available at Maven Central (see the KosherJava Downloads page for instructions). The old code was branched into zmanim-1.5 and will allow people who do not want to upgrade to continue to use the old structure (and Ant build process) while continuing to receive emergency bug fixes. This will allow the codebase to use more modern Java language features, without impacting users who want to remain on the legacy code. The new code has a minimum Java 8 requirement (a version released in March 2014). Releases based on the new build process will use SemVer (Semantic Versioning) to make things simpler for developers.
The upgraded build process also allowed automated GitHub’s CodeQL vulnerability scanning for the KosherJava Zmanim project.
You can add the KosherJava zmanim library as a Maven or Gradle dependency. For Maven add the following to your pom.xml.

<dependency>
  <groupId>com.kosherjava</groupId>
  <artifactId>zmanim</artifactId>
  <version>2.0.3</version>
</dependency>

For Gradle, add the following to your build.gradle file.

implementation group: 'com.kosherjava', name: 'zmanim', version: '2.0.3'

Parsha Code Restored to the KosherJava Zmanim Calendar API

In the Parsha Code Removed from KosherJava Zmanim Calendar API article posted two years ago, I documented the removal of the parsha code from the KosherJava Zmanim API due to licensing issues. I would like to announce that thanks to Yechiel Paricher, the zmanim library now supports a clean LGPL implementation. Yechiel’s Jan 17, 2019 pull request that was a port of his C libzmanim code, was finally merged on August 22nd, and over the past day, the old formatting code for parshiyos was restored after being changed to work with the new code. The new code not only restores the old functionality, but adds support for the special parshiyos of Shekalim, Zachor, Parah and Hachodesh. It also added support for Shabbos Mevorchim and Machar Chodesh.

Parsha Code Removed from KosherJava Zmanim Calendar API

Due to licensing issues that were brought to my attention last year, the parsha code was removed from the Zmanim API on Aug 22, 2016. In the future I may release the parsha code as a standalone module under the GPL license, or create a new LGPL implementation. To understand this more clearly, the current Zmanim API is licensed under the LGPL, while the parsha code contained some GPL code that had to be removed in order to retain the LGPL license. I would welcome any code submission for parsha code that could be released under the LGPL.

Update: Parsha Code Restored

On November 17, 2019 – י״ט מרחשון תש״פ an updated post Parsha Code Restored to the KosherJava Zmanim Calendar API announced the restoration of the parsha functionality.

FAQ: Different Parshas Hashavua in Eretz Yisrael Than Chutz La’aretz

Question:

Why does the KosherJava Zmanim API seem to sometimes return the incorrect parshas hashavua in Israel?

Answer:

I have had a number of inquiries this year about the incorrect Parshas Hashavua being returned by the API. In all cases this has been a complaint for Eretz Yisrael and not Chutz La’aretz. The explanation is pretty simple and covered in the API documentation for the JewishCalendar class, but may not be clear to all. When the first day of Pesach occurs on a Shabbos, as it did this year (5775), the last day of Pesach in Eretz Yisrael is on a Friday. The following day is a regular Shabbos in Eretz Yisrael with the usual krias hatorah, but in chutz la’aretz it is the 8th day of Pesach, resulting in krias Hatorah for Pesach. The following weeks will have different krias HaTorah in Eretz Yisrael vs chutz la’aretz, and this will continue for a number of weeks until a double parsha in chutz laaretz is added to equalize the parsha. This last occurred in 2012 (before the release of the calendar functionality in the Zmanim 1.3 release) and will occur again next year. If you are coding to display the Parshas Hashavuah for use in Israel, it is important to set the inIsrael(true) flag (it has a default of false).

JewishDate.setInIsrael(true);

A fuller example showing how to set the indicator and showing the comparison of Eretz Yisrael and Chutz Laaretz this year can be seen in this example.

JewishCalendar israelCalendar = new JewishCalendar(5775, JewishDate.NISSAN, 7);
israelCalendar.setInIsrael(true); //set the calendar to Israel
JewishCalendar chutsLaaretzCalendar = new JewishCalendar(5775, JewishDate.NISSAN, 7);
chutsLaaretzCalendar.setInIsrael(false); //not really needed since the API defaults to false
HebrewDateFormatter hdf = new HebrewDateFormatter();
System.out.println("Date\tChutz Laaretz / Eretz Yisrael"));
for(int i = 0; i < 57; i++){
	israelCalendar.forward(); //roll the date forward a day
	chutsLaaretzCalendar.forward(); //roll the date forward a day
	if(chutsLaaretzCalendar.getDayOfWeek() == 7){ //ignore weekdays
		System.out.println(hdf.formatParsha(chutsLaaretzCalendar) + "\t" + hdf.formatParsha(israelCalendar) + " \\ " + hdf.format(chutsLaaretzCalendar));
	}
}

the output of this is

Date               Chutz Laaretz / Eretz Yisrael
8 Nissan, 5775     Tzav / Tzav
15 Nissan, 5775     / 
22 Nissan, 5775     / Shmini
29 Nissan, 5775    Shmini / Tazria Metzora
6 Iyar, 5775       Tazria Metzora / Achrei Mos Kedoshim
13 Iyar, 5775      Achrei Mos Kedoshim / Emor
20 Iyar, 5775      Emor / Behar
27 Iyar, 5775      Behar Bechukosai / Bechukosai
5 Sivan, 5775      Bamidbar / Bamidbar

It should be noted that this discrepancy is not rare and happens about 25% of the calendar years.

FAQ: Calculating the Baal Hatanya’s Shkiah

Baal Hatanya Zmanim

Please see the more recent and updated article Baal Hatanya’s Zmanim Added to KosherJava Zmanim Library for more current information.

Question:

How do I calculate the בעל התניא Baal Hatanya’s Zman for Shkiah as 4 minutes after sunset using the KosherJava Zmanim API?

Answer:

I was recently asked how to use the Zmanim API to calculate the Baal Hatanya’s opinion is that shkiah (halachic sunset) is 4 minutes after civil sunset. The assumption that the Baal Hatanya’s shkiah is a fixed 4 minutes after sunset is not that simple and will require a separate post to clarify. This zman should not be used lehalacha without consulting a rov. This post shows how to us the API assuming that it is a fixed 4 minutes after sunset. The technique to calculate this with the API is identical to the way getTzais72() would be calculated. The source of that method is

public Date getTzais72() {
return getTimeOffset(getSeaLevelSunset(), 72 * MINUTE_MILLIS);
}

The getTimeOffset(Date time, double offset) method in the base class AstronomicalCalendar is very simple:

public Date getTimeOffset(Date time, long offset) {
if (time == null || offset == Long.MIN_VALUE) {
return null;
}
return new Date(time.getTime() + offset);
}

The getTimeOffset method simply adds the number of milliseconds of the offset to the raw time of the zman and returns it as a date. While using the API itself is not needed for such a simple calculation, here is how it would be used:

String locationName = "Jerusalem";
double latitude = 31.778; // Har habayis
double longitude = 35.2354;// Har Habayis
double elevation = 0;
TimeZone timeZone = TimeZone.getTimeZone("Asia/Jerusalem");
GeoLocation location = new GeoLocation(locationName, latitude, longitude, elevation, timeZone);
ZmanimCalendar zc = new ZmanimCalendar(location);
Date baalHatanyaShkiah = zc.getTimeOffset(zc.getSeaLevelSunset(), 4 * 60000);
System.out.println("Baal Hatanya Shkiah: " + baalHatanyaShkiah);

Adding it to the API itself would be even simpler:

public Date getShkiahBaalHatanya() {
return getTimeOffset(getSeaLevelSunset(), 4 * MINUTE_MILLIS);
}

At some point in the future I may (doubtful) add this time to the API itself. The zman is not commonly used, and the Chabad calendars that I have seen all use regular sunset.

Update on ‍‍July 5, 2015 – י״ח תמוז תשע״ה: This article was updated to clarify that the Baal Hatanya’s opinion may not be a fixed 4 minutes, but that the post was showing how to use the API to calculate it based on the questioner’s assumption that it was a 4 minute zman.
Update on Dec 14, 2018 – ו׳ טבת תשע״ט: This article was superseded with the more recent and corrected article Baal Hatanya’s Zmanim Added to KosherJava Zmanim Library.