In this tutorial, we'll focus on how to install Java 8 on Ubuntu 18.04 from the terminal. By default, Ubuntu 18.04 comes with Java 11.
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 OpenJDK 8
By default Ubuntu 18.04 comes with Java 11. Many applications still use Java 8.
To install OpenJDK 8, run the following command:
apt update
apt install openjdk-8-jdk
How to install Oracle JDK 8
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
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'.
You'll then be prompted to accept the license agreement. Use the Cursor Keys and Press 'Enter' on 'Yes'.
How to Install default JDK/JRE (Java 11)
This is the easiest option when installing Java since it comes packaged with the Ubuntu system. This will install OpenJDK 11 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
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.
The default-jdk package comes with JRE, so there's no need to install JRE once you've installed JDK. At the time of writing, the default JDK installs Java OpenJDK 11 version.
To install default JDK, run
apt-get install default-jdk
Checking Java version
To verify that we have Java installed and check out the version, run the command below.
java -version
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
Related Read:
- How to Install Java 8 on Debian GNU/Linux 9 (Stretch)
- How Install java and Set Environment Variables RHEL / CentOS
In this tutorial, we have outlined the steps on how you can install Java 8 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.
