picocli

Includes an annotation processor to automatically Graal-enable jars, enabling ahead-of-time compilation to fast-starting, low-memory native executables, as highlighted in the README's focus on GraalVM integration.

Offers ANSI-colored help, TAB autocompletion for bash/zsh, and nested subcommands, making it suitable for complex, user-friendly command-line interfaces without boilerplate code.

With annotations, commands can be defined in a single line; implementing Runnable or Callable delegates parsing and help handling to picocli, reducing development time.

Packaged as a single source file, allowing applications to include it directly and avoid external dependency management, as noted in the README's philosophy.