How to codegen java with ragel rules

[tutufool]

Hi, ragel team

I just found some docs: (not sure if it's up to date)
http://manpages.ubuntu.com/manpages/bionic/man1/ragel.1.html

According to the doc, I need to apply options:

-J The host language is Java.

-T0 (C/D/Java/Ruby/C#/Go) Generate a table driven FSM. (it seems -T0 is the only option)

What else options are recommended or nice to have?

Could you give me some instruction on that? like providing a sample command with proper options.

Thanks in advance!

Leon