You can uninstall or removes an installed libconcurrentlinkedhashmap-jav package itself from Debian 8 (Jessie) through the terminal,
$ sudo apt-get remove libconcurrentlinkedhashmap-jav
If you would like to remove libconcurrentlinkedhashmap-jav and it's dependent packages which are no longer needed from Ubuntu,
$ sudo apt-get remove --auto-remove libconcurrentlinkedhashmap-jav
If you use with purge options to libconcurrentlinkedhashmap-jav package all the configuration and dependent packages will be removed.
$ sudo apt-get purge libconcurrentlinkedhashmap-jav
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 libconcurrentlinkedhashmap-jav