Apache Tomcat is an open-source implementation of the Java Servlet, JavaServer Pages, Java Expression Language and WebSocket technologies.
Bootstrap is a free and open-source CSS framework directed at responsive, mobile-first front-end web development. It contains CSS and JavaScript-based design templates for typography, forms, buttons, navigation, and other interface components.
cdnjs is a free distributed JS library delivery service.
Java is a class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible.
jQuery CDN is a way to include jQuery in your website without actually downloading and keeping it your website's folder.
jQuery is a JavaScript library which is a free, open-source software designed to simplify HTML DOM tree traversal and manipulation, as well as event handling, CSS animation, and Ajax.
Popper is a positioning engine, its purpose is to calculate the position of an element to make it possible to position it near a given reference element.
Pure CSS is a set of small, responsive CSS modules that can be used in web projects.
Unpkg is a content delivery network for everything on npm.