You can uninstall or removes an installed libjstun-java package itself from Ubuntu 16.04 LTS (Xenial Xerus) through the terminal,
$ sudo apt-get remove libjstun-java
If you would like to remove libjstun-java and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove libjstun-java
If you use with purge options to libjstun-java package all the configuration and dependent packages will be removed.
$ sudo apt-get purge libjstun-java
If you use purge options along with auto remove, will be removed everything regarding the package, It's really useful when you want to reinstall again.
$ sudo apt-get purge --auto-remove libjstun-java