TL:DR; Java Mail library.
Java Mail library. This is a small java package that can send and receive emails. Including MIME and attachements.
JavaScript Drop Down Menu is a fully-featured and accessible menu, that provides useable content to all browsers - including screenreaders, search-engines and text-only browsers.
License4J is a Java library for java software licensing. It is designed to be easy to use and integrate in your Java application. License4J creates license files and secure serial numbers. Includes a free to use,distribute floating license server.
Mouse Gestures is an open source (LGPL) pure Java library for recognition and processing mouse gestures. With Mouse Gestures you have a fast way to execute commands without using the keyboard, menus or toolbars.