ubuntu-debian-JDK.md

DEFAULT

sudo apt-get update

JRE (Java Runtime Environment)

sudo apt-get install default-jre

JDK (Java Development Kit)

sudo apt-get install default-jdk

Installing the Oracle JDK

sudo add-apt-repository ppa:webupd8team/java
sudo apt-get update

6 or 7 or else Oracle JDK

sudo apt-get install oracle-java6-installer

sudo apt-get install oracle-java7-installer

sudo apt-get install oracle-java8-installer

sudo apt-get install oracle-java9-installer

Update Alternative

sudo update-alternatives --config java

JAVA_HOME Environment

Copy file path

sudo update-alternatives --config java

Edit /etc/environment (nano / vi / gedit / leafpad whatever)

sudo nano /etc/environment

Copy and paste path (java 6~9)

JAVA_HOME="/usr/lib/jvm/java-8-oracle"

use it now.

source /etc/environment

check it

echo $JAVA_HOME