$ sudo add-apt-repository ppa:openjdk-r/ppa
$ sudo apt-get update
$ sudo apt-get install openjdk-8-jdk
インストール確認
$ java -version
openjdk version "1.8.0_72-internal"
OpenJDK Runtime Environment (build 1.8.0_72-internal-b15)
OpenJDK 64-Bit Server VM (build 25.72-b15, mixed mode)