How to install Java JDK 8 on Linux

### Sign as root ###
su

### Before you start with the setting up Java, you will need to remove the OpenJDK/JRE from the system ###
apt-get purge openjdk-\*

### Check whether Ubuntu OS architecture is 32-bit or 64-bit ###
neofetch

### Download the Java JDK and extract it somewhere ###
Link: https://archive.org/details/jdk-8u301-linux-umarkovwebsite

### Create "java" folder in the root directory ###
Create a folder (sign in as root first!) named "java" in the root dir and set the permission to 755 or 777.

### Set the permission of that "java" folder ###
To do this: "sudo chmod -R (755 or 777) /java"

### Make sure you create directory as described below ###
It will look like this: "/java/(PUT YOUR JDK FOLDER VERSION HERE)/"
Example: "/java/jdk1.8.0_301"

### Add the following system variables to the end of /etc/profile file ###
### To do so: "nano /etc/profile" ###
JAVA_HOME=/java/jdk1.8.0_301
PATH=$PATH:$HOME/bin:$JAVA_HOME/bin
export JAVA_HOME
export PATH

### Save it (ctrl+s) and exit (ctrl+x) ###

### Now reload the enviorment ###
. /etc/profile

### Its time to let Ubuntu know where our JDK/JRE is located ###
### Copy-paste below lines into a command prompt ###
update-alternatives --install "/usr/bin/java" "java" "/java/jdk1.8.0_301/bin/java" 1
update-alternatives --install "/usr/bin/javac" "javac" "/java/jdk1.8.0_301/bin/javac" 1
update-alternatives --install "/usr/bin/javaws" "javaws" "/java/jdk1.8.0_301/bin/javaws" 1

### Tell Ubuntu that our installation i.e., jdk1.8.0_05 must be the default Java ###
update-alternatives --set java /java/jdk1.8.0_301/bin/java
update-alternatives --set javac /java/jdk1.8.0_301/bin/javac
update-alternatives --set javaws /java/jdk1.8.0_301/bin/javaws

### Test the installation using below command ###
java -version

### DONE!! ###