checkstyle software package provides checks Java source against a coding standard, 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 checkstyle
checkstyle is installed in your system.
Make ensure the checkstyle package were installed using the commands given below,
$ sudo dpkg-query -l | grep checkstyle *
You will get with checkstyle package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Java |
| Package | checkstyle |
| Version | 6.15-1 |
| Description | checks Java source against a coding standard |
| Sub Section | Java |