jetty9 software package provides Java servlet engine and webserver, 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 jetty9
jetty9 is installed in your system.
Make ensure the jetty9 package were installed using the commands given below,
$ sudo dpkg-query -l | grep jetty9 *
You will get with jetty9 package name, version, architecture and description in a table
| Distro | Debian 9 stretch |
| Section | Java |
| Package | jetty9 |
| Version | 9.2.19-2 |
| Description | Java servlet engine and webserver |
| Sub Section | Java |