I too am having trouble with this on my Windows computer. I got it in a jar file, then I tried opening it, executing it, and there were only folders wither random letters, no exe programs! Please help me!
Please note that the JAR file is the executable here, no EXE.
Apparently, your computer extracts the contents of the JAR instead of running it. Open your console and execute java -jar [path to file]
to run the generator.
One suggestion though would be to have a preview option so that the user can see what the final product will look like without the need to head into minecraft after each change and give themselves the book.