Before Java 8, JDK’s data and time libraries have so many flaws, because they were not thread-safe, immutable, and error-prone. Many Java developers relied on JodaTime for implementing their date and time requirements.

From JDK 8, there is no reason to use Joda, because you get all that functionality in the JDK 8’s new date and time API, but if you are working in an older Java version, then JodaTime is a worth learning library.

If you want to learn more about the new date and time API, I suggest you check the Java 8 New Features In Simple Way course on Udemy. It provides a nice overview of all the important features of Java 8, including the date and time API.