How to install Java 8 on ubuntu ?

Install Java-8-oracle

Make sure your PC is connected to internet.

Open terminal (press window key and search for "terminal")

Switch to root

$ sudo sh

Run following commands in sequence :

# sudo add-apt-repository ppa:webupd8team/java
# sudo apt-get update
# sudo apt-get install oracle-java8-installer
* If installation interrupted in between, run command : 
# sudo dpkg --configure -a
 

After installation, check if Java is installed : 
java -version