First, update the package index.
sudo apt-get update
sudo apt-get upgrade
The easiest way is installing Java by using version packaged with Ubuntu. Following steps will install OpenJDK 8.
This command will install the Java Runtime Environment (JRE).
sudo apt-get install default-jre
After installation you can validate it by entering command
It should give you response with installed Java version like
openjdk version "1.8.0_111"
OpenJDK Runtime Environment (build 1.8.0_111-8u111-b14-2ubuntu0.16.10.2-b14)
OpenJDK 64-Bit Server VM (build 25.111-b14, mixed mode)
If you are going to compile Java programs, deploy portlets please install JDK (Java Development Kit).
Please notice JDK does contain JRE so you can only install JDK to get the system running.
sudo apt-get install default-jdk
Validate JDK installation by entering command
It should give you response with JDK version like
Set JAVA_HOME enviroment variable by opening environment file
sudo nano /etc/environment
save file and refresh environment
You can check JAVA_HOME enviroment variable by typing
and it will return path to java home as you just added to environment