A JavaFX Game Application in a Single Java File with JBang and FXGL

FXGL is a JavaFX-based game development framework, and combined with JBang it becomes possible to build and run a complete game from a single Java file without any Maven or Gradle project setup. The post walks through the required technologies (JBang, FXGL, and a JavaFX-bundled JDK via SDKMAN! or Azul), the JBang configuration header for dependency management, and the structure of the example game code including the main GameApplication class, an EntityFactory, and Component inner classes for player and enemy entities. The full source is available on GitHub and can be launched with a single `jbang` command.