Why the absence of joda, org.joda.time.DateTime?

Question

Java

Why is this directory missing and where does it come from?

Answer 1

This is the library, www.joda.org/joda-time/.
It is missing, for example, because it is not included, since it is not a standard library included in the JDK.
To work with it, you need to include it in your IDE in one way or another - it all depends on the type of project and IDE.
The easiest way to add it to a Maven project is to simply add the desired artifact to pom.xml:

<dependency>
  <groupId>joda-time</groupId>
  <artifactId>joda-time</artifactId>
  <version>2.9.7</version>
</dependency>