Openfire (previously known as Wildfire, and Jive Messenger) is an instant messaging (IM) and groupchat server that uses XMPP server written in Java and licensed under the Apache License 2.0.
You can use WebUpd8 PPA (this will download the required files from Oracle and install JDK 8)
sudo apt-add-repository ppa:webupd8team/java sudo apt-get update sudo apt-get install oracle-java8-installerhttp://www.igniterealtime.org/downloads/index.jsp download it from above site
You may also, use following wget command to download package and install it using dpkg command as shown below.
On Debian/Ubuntu/Linux Mint
# wget http://download.igniterealtime.org/openfire/openfire_3.10.2_all.deb # dpkg -i openfire_3.10.2_all.deb