An example of a Java program that can be executed as a shell script.

java-shell-script

#!/usr/bin/java --source 17

public class EchoArguments {
    public static void main(String[] args) {
        System.out.printf("Arguments: %s%n", String.join(", ", args));
    }
}

This ability has existed since Java 11, although this script utilises some Java 17 features as well.

Three requisites:

1. The file must be executable, i.e: chmod u+x java-shell-script
2. The filename must not have a .java extension. (This caught me out for some time).
3. The file may contain multiple classes. Precisely one of them must have a static main method with the usual signature.