http://tipsonubuntu.com/2016/07/31/install-oracle-java-8-9-ubuntu-16-04-linux-mint-18/
Quick tutorial for beginners how to easily install Oracle Java JDK8 or JDK9 in Ubuntu 16.04 or Linux Mint 18 via PPA.
Webupd8 Teamis maintaining a PPA repository with installer scripts for the latest Java 8 and 9,that automatically downloads the Java archive from Oracle website and sets up everything for you.
1. Add the PPA.
Open terminal (Ctrl+Alt+T) and run the command:
sudo add-apt-repository ppa:webupd8team/java
Type in your password when it asks and hit Enter.
2. Update and install the installer script:
Run commands to update system package index and install Java installer script:
sudo apt update; sudo apt install oracle-java8-installer
You may replace oracle-java8-installer withoracle-java9-installerto install Java 9.
While the install process,you have to accept Java license to continue downloading & installing Java binaries.
To check the Java version after installing the package,run command:
javac -version
4. Set Java environment variables
The PPA also contains a package to automatically set Java environment variables,just run command:
sudo apt install oracle-java8-set-default
For Java 9,install the packageoracle-java9-set-defaultinstead.
原文链接：https://www.f2er.com/oracle/206710.html