f2j software package provides Fortran to Java compiler, you can install in your Debian 9 (Stretch) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install f2j
f2j is installed in your system.
Make ensure the f2j package were installed using the commands given below,
$ sudo dpkg-query -l | grep f2j *
You will get with f2j package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Java |
| Package | f2j |
| Version | 0.8.1+dfsg-2 |
| Description | Fortran to Java compiler |
| Sub Section | Java |