JavaFX
JavaFX is a modern, cross-platform GUI framework for building rich client applications in Java. It provides a set of graphics and media APIs for creating desktop, mobile, and embedded applications with advanced UI components, 2D/3D graphics, and multimedia support. It has largely replaced Swing as the standard GUI toolkit for Java applications.
Developers should learn JavaFX when building desktop applications that require modern, visually appealing user interfaces with features like animations, charts, and media playback. It's particularly useful for business applications, data visualization tools, and educational software where cross-platform deployment (Windows, macOS, Linux) is essential. JavaFX integrates well with the Java ecosystem, making it a natural choice for Java developers needing GUI capabilities.