Tip: Using Calendar.getInstance()

Learn why you should avoid using the Calendar.getInstance() in many instances.

by Octavia Anghel

Jan 24, 2018

Calendar c = Calendar.getInstance();
c.set(2017, Calendar.OCTOBER, 29);

The code above behaves as a Gregorian calendar, but if the returned Calendar subclass is an Islamic, Julian, Buddist or Hebrew calendar, the month called October or the year 2017, doesn't exist. Calendar.getInstance() uses the current default locale to select an appropriate implementation. The utility of Calendar.getInstance() is very limited and it should be avoided because the results are not properly defined.

Calendar c = new GregorianCalendar (timeZone);
c.set(2017, Calendar.OCTOBER, 29);

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Octavia Andreea Anghel is a senior PHP developer currently working as a primary trainer for programming teams that participate at national and international software-development contests. She consults on developing educational projects at a national level. She is a coauthor of the book "XML Technologies--XML in Java" (Albastra, ISBN 978-973-650-210-1), for which she wrote the XML portions. In addition to PHP and XML, she's interested in software architecture, web services, UML, and high-performance unit tests.