Install Graylog 3.0 on Ubuntu 18.04 / Ubuntu 16.04

OpenJDK 8.

sudo apt update
sudo apt install -y apt-transport-https openjdk-8-jre-headless uuid-runtime pwgen curl dirmngr

Verify the Java version.

java -version

Output:

openjdk version "1.8.0_191"
OpenJDK Runtime Environment (build 1.8.0_191-8u191-b12-2ubuntu0.18.04.1-b12)
OpenJDK 64-Bit Server VM (build 25.191-b12, mixed mode)