Linux mint 18 mate comes with open JDk 8 by default. Open JDK and Oracle JDK both have almost the same code of the classes in the Java API. But OpenJDK tends to use open libraries and Oracle JDK tends to use closed ones. And if you want to install Oracle JDK 8 on Linux Mint, please follow the below steps.
Install Oracle JDK 8 on Linux Mint 18
Go to Oracle JDK8 download page. And download the latest linux jdk in .tar.gz format.
Here its (32 bit) jdk-8u102-linux-i586.tar.gz
Note:change the JDK version in the command according to your jdk version.
Copy your JDK .tar.gz file to your Desktop.
Open Terminal. To open terminal click the Main Linux Mint Menu, then go to system tools and select Terminal or type terminal in the search field or click the Terminal icon in taskbar.