jwm software package provides very small lightweight pure X11 window manager with tray and menus, you can install in your Ubuntu 16.04 LTS (Xenial Xerus) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install jwm
jwm is installed in your system.
Make ensure the jwm package were installed using the commands given below,
$ sudo dpkg-query -l | grep jwm *
You will get with jwm package name, version, architecture and description in a table
| Distro | Ubuntu 16 04 lts xenial xerus |
| Section | X Window System software |
| Package | jwm |
| Version | 2.3.5-2 |
| Description | very small lightweight pure X11 window manager with tray and menus |
| Sub Section | X330 |