Day.js is a minimalist JavaScript library that parses, validates, manipulates, and displays dates and times for modern browsers with a largely Moment.js-compatible API. If you use Moment.js, you already know how to use Day.js.

Joda-Time provides a quality replacement for the Java date and time classes.

Joda-Time is the de facto standard date and time library for Java prior to Java SE 8. Users are now asked to migrate to java.time (JSR-310).

Joda-Time is licensed under the business-friendly Apache 2.0 licence.