How to Install Java 8 on Ubuntu 18.04

In this article, we'll focus on how to install java on Ubuntu 18.04 from the terminal. We will begin by installing the default JDK/JRE. Java is an application that is a prerequisite in a wide range of software such as Tomcat Web server, Netbeans IDE, Glassfish server to mention just but a few.

How to install default JDK/JRE

This is the easiest option when installing Java since it comes packaged with Ubuntu system. This will install OpenJDK 8 which is the recommended version. First off, let's update the system. Log in as root user and run the command below

apt update

Next, Install Java Runtime Environment

apt-get install default-jre

Sample Output

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  ca-certificates-java default-jre-headless fonts-dejavu-extra java-common
  libatk-wrapper-java libatk-wrapper-java-jni libgif7 openjdk-11-jre
  openjdk-11-jre-headless
Suggested packages:
  default-java-plugin fonts-ipafont-gothic fonts-ipafont-mincho
  fonts-wqy-microhei | fonts-wqy-zenhei
The following NEW packages will be installed:
  ca-certificates-java default-jre default-jre-headless fonts-dejavu-extra
  java-common libatk-wrapper-java libatk-wrapper-java-jni libgif7
  openjdk-11-jre openjdk-11-jre-headless

On the other hand, there exists a default Java installation popularly known as JDK, short for Java Development Kit. This is commonly used with IDE's such as Eclipse and Netbeans for compiling Java programs. It already comes with JRE, so there's no need of installing JRE once you've installed JDK.
To install JDK, run

apt-get install default-jdk

Sample Output

The following additional packages will be installed:
  default-jdk-headless libice-dev libpthread-stubs0-dev libsm-dev libx11-dev
  libx11-doc libxau-dev libxcb1-dev libxdmcp-dev libxt-dev openjdk-11-jdk
  openjdk-11-jdk-headless x11proto-core-dev x11proto-dev xorg-sgml-doctools
  xtrans-dev
Suggested packages:
  libice-doc libsm-doc libxcb-doc libxt-doc openjdk-11-demo openjdk-11-source
  visualvm
The following NEW packages will be installed:
  default-jdk default-jdk-headless libice-dev libpthread-stubs0-dev libsm-dev
  libx11-dev libx11-doc libxau-dev libxcb1-dev libxdmcp-dev libxt-dev
  openjdk-11-jdk openjdk-11-jdk-headless x11proto-core-dev x11proto-dev
  xorg-sgml-doctools xtrans-dev

How to install Oracle JDK

If you want to be more specific and install Oracle JDK, you'll be required to add Oracle's PPA.

add-apt-repository ppa:webupd8team/java

Sample Output

Get:1 http://ppa.launchpad.net/webupd8team/java/ubuntu bionic InRelease [15.4 kB]
Hit:2 http://ke.archive.ubuntu.com/ubuntu bionic InRelease
Hit:3 http://ke.archive.ubuntu.com/ubuntu bionic-updates InRelease
Hit:4 http://ke.archive.ubuntu.com/ubuntu bionic-backports InRelease
Hit:5 http://linux.teamviewer.com/deb stable InRelease
Hit:6 http://linux.teamviewer.com/deb preview InRelease
Get:7 http://ppa.launchpad.net/webupd8team/java/ubuntu bionic/main i386 Packages [1,556 B]
Get:8 http://ppa.launchpad.net/webupd8team/java/ubuntu bionic/main amd64 Packages [1,556 B]
Get:9 http://ppa.launchpad.net/webupd8team/java/ubuntu bionic/main Translation-en [928 B]

Next, update the system.

apt update

Install Oracle JDK 8 which is the most stable version by running the command below

apt-get install oracle-java8-installer

The following pop up will be displayed. Press 'Enter'.

install Java on Ubuntu

You'll then be prompted to accept the license agreement. Use the Cursor Keys and Press 'Enter' on 'Yes'.

install Java on Ubuntu

Sample Output

Preconfiguring packages ...
Selecting previously unselected package oracle-java8-installer.
(Reading database ... 131873 files and directories currently installed.)
Preparing to unpack .../oracle-java8-installer_8u171-1~webupd8~0_all.deb ...
Unpacking oracle-java8-installer (8u171-1~webupd8~0) ...
Setting up oracle-java8-installer (8u171-1~webupd8~0) ...
No /var/cache/oracle-jdk8-installer/wgetrc file found.
Creating /var/cache/oracle-jdk8-installer/wgetrc and
using default oracle-java8-installer wgetrc settings for it.
Downloading Oracle Java 8...

Checking Java version

To verify that we have Java installed and check out the version, run the command below.

java -version

Sample Output

java version "1.8.0_171"
Java(TM) SE Runtime Environment (build 1.8.0_171-b11)
Java HotSpot(TM) 64-Bit Server VM (build 25.171-b11, mixed mode)

How to manage Java

As seen above we have a few Java installation in our system, and as good practice, It's advisable to set the default Java version. To achieve this, e have to run the command below

update-alternatives --config java

Sample Output

  Selection    Path                                         Priority   Status
------------------------------------------------------------
  0            /usr/lib/jvm/java-11-openjdk-amd64/bin/java   1101      auto mode
  1            /usr/lib/jvm/java-11-openjdk-amd64/bin/java   1101      manual mode
* 2            /usr/lib/jvm/java-8-oracle/jre/bin/java       1081      manual mode
Press  to keep the current choice[*], or type selection number:

Scroll using the cursor keys and Press Enter on your preferred java installation.

Finally, we need to set the JAVA_HOME environment variable.

How to set up the JAVA_HOME environment variable

To do so, Open /etc/environment

 nano /etc/environment

Add the path to your preferred java installation

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

Press 'CTRL + O' to Save and CTRL + X' to exit nano editor.

Reload by running

source /etc/environment

To verify that all went well run the following command.

echo $JAVA_HOME

This should display the path specified

Sample Output

/usr/lib/jvm/java-8-oracle/jre/bin/java

How to uninstall Oracle Java

To completely remove Oracle Java from your system, first, run the commands below to check which version is installed

dpkg --list | grep -i jdk

Output

ii oracle-java8-installer 8u171-1~webupd8~0 all Oracle Java(TM) Development Kit (JDK) 8
ii oracle-java8-set-default 8u171-1~webupd8~0 all Set Oracle JDK 8 as default Java

To remove Oracle Java 8, run

apt-get purge oracle-java8-installer

Sample Output

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following package was automatically installed and is no longer required:
  gsfonts-x11
Use 'sudo apt autoremove' to remove it.
The following packages will be REMOVED:
  oracle-java8-installer* oracle-java8-set-default*
0 upgraded, 0 newly installed, 2 to remove and 382 not upgraded.
After this operation, 138 kB disk space will be freed.
Do you want to continue? [Y/n]

Recommended read :

In this post, we have outlined the steps on how you can install Java on Ubuntu 18.04. Java is crucial for a number of software applications as mentioned earlier such as Tomcat server. Feel free to try these steps out. Stay tuned for more insightful articles from us.

Jamie Arthur 2:19 am

About Jamie Arthur

Hey, I'm James, a passionate Linux Systems administrator, and a tech enthusiast. I derive immense gratification in conducting research on Linux systems and keeping myself up to date with the latest in the technology world.

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