Java is a class-based, object-oriented programming language that is designed to have as few implementation dependencies as possible. It is a general-purpose programming language intended to let application developers write once, and run anywhere (WORA), meaning that compiled Java code can run on all platforms that support Java without the need for recompilation. Click for more on Wikipedia.
We need a machine with Ubuntu 16.04 installed for a non-root user with
sudo authority in order to have Java working in your hand.
JRE/ OpenJDK Setup
First is first, let's get updates.
sudo apt-get update
We need JRE (Java Runtime Environment) for running java applications.
sudo apt-get install default-jre
If we want to develop any java code, we need to setup JDK (Java Development Kit);
sudo apt-get install default-jdk
Let's check java version;
openjdk version "1.8.0_181" OpenJDK Runtime Environment (build 1.8.0_181-8u181-b13-0ubuntu0.16.04.1-b13) OpenJDK 64-Bit Server VM (build 25.181-b13, mixed mode)
You should see a newer version of java. When I write this article, the latest version was 1.8.
Oracle JDK Setup (if you prefer)
First of all, we need to install Oracle's PPA. For more detail about PPA
sudo add-apt-repository ppa:webupd8team/java $ sudo apt-get update
sudo apt-get install oracle-java8-installer
sudo apt-get install oracle-java9-installer
For managing default java;
sudo update-alternatives --config java
(If you install 2 or more java);
There are 5 choices for the alternative java (providing /usr/bin/java). Selection Path Priority Status ------------------------------------------------------------ * 0 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 auto mode 1 /usr/lib/jvm/java-6-oracle/jre/bin/java 1 manual mode 2 /usr/lib/jvm/java-7-oracle/jre/bin/java 2 manual mode 3 /usr/lib/jvm/java-8-openjdk-amd64/jre/bin/java 1081 manual mode 4 /usr/lib/jvm/java-8-oracle/jre/bin/java 3 manual mode 5 /usr/lib/jvm/java-9-oracle/bin/java 4 manual mode Press <enter> to keep the current choice[*], or type selection number:
JAVA_HOME Environment Settings
Let's edit the environment file;
sudo nano /etc/environment
Test JAVA_HOME variable;
We currently have a fully working Java installation in our operating system. Also, we setup the JAVA_HOME environment variable. As of now we can run/develop java applications.