Java is one of the most robust programming languages for developing websites, games, Android, and desktop apps.

And to check whether java is already installed on your system, you can use the following:

java --version

And if it comes up with any version number, you have it already installed, and if it shows an error saying Command 'java' not found, here you have various ways to java on Ubuntu.

How to Install Java in Ubuntu

There are two ways to install Java in Ubuntu:

• Using the JDK package
• Using JRE package

The JDK packages contain every essential package that the user needs to run a java application.

Whereas the JRE has some additional tools to facilitate the development process.

One thing to remember is that JDK has an Oracle version used for commercial purposes.

Although there are no significant differences between Oracle JDK and OpenJDK, Oracle JDK offers higher performance and responsiveness.

Oracle JDK mainly focuses on stability, best suited for enterprise purposes.

To install JDK:

So if you want the JDK package, all you have to do is execute the following command:

sudo apt update && sudo apt install default-jdk

Once you are done with the installation, you can check the installed version of java to verify the installation:

java --version

prateek@Learnubuntu:~$ java --version
openjdk 11.0.18 2023-01-17
OpenJDK Runtime Environment (build 11.0.18+10-post-Ubuntu-0ubuntu122.04)
OpenJDK 64-Bit Server VM (build 11.0.18+10-post-Ubuntu-0ubuntu122.04, mixed mode, sharing)

To install Open JRE (optional):

So if you are into software development, installing JRE can come in handy.  

To install JRE, all you have to do is execute the following command:

sudo apt install default-jre

Install Specific Version of Java

The default repository allows you to choose from various versions of JDK and JRE so if your workflow demands a different version, here you have it.

To list available versions of java, use the following command:

apt list OpenJDK\*

Here, I will walk you through how you can install a specific version of both JDK and JRE.

Will start with the JDK.

To install the specific version of JDK on Ubuntu

So if you want to install a specific version of JDK, you will have to execute the apt in the following manner:

sudo apt install openjdk-[version_no]-jdk

For your reference, here, I installed the JDK version 17:

sudo apt install openjdk-17-jdk

To install a specific version of JRE on Ubuntu

So if you are looking to install a specific version of JRE, you will have to execute the apt in the following manner:

sudo apt install openjdk-[version_no]-jre

For example, if I want to install JDK version 17, then I will be using the following command:

sudo apt install openjdk-17-jre

Install Oracle JDK in Ubuntu

Sadly, the Oracle JDK is not available in the default repository of Ubuntu so you will have to install the Debian package in Ubuntu manually.

To do so, first, visit the official download page of oracle java and choose between java 17 or 19.

And there, you will find the deb package available:

You may copy the link and download it via wget or use your browser. It is all up to you and I will be using wget to download the package:

wget https://download.oracle.com/java/17/latest/jdk-17_linux-x64_bin.deb

Once done, you can easily install the downloaded deb package:

sudo apt install ./jdk-17_linux-x64_bin.deb

Make sure to change the package name accordingly!

Setup JAVA_HOME Environment

Setting up the home environment is not absolutely necessary but some packages like tomcat require this and queries while booting.

So the first step is to check whether you have installed multiple versions of java. If so, the following command will give you the list and path of each one:

sudo update-alternatives --config java

Also, copy the path of the selected version. I went with the JDK 17 here.

Next, open the environment file using the following command:

sudo nano /etc/environment

Go to the end of the line in nano using Alt + / and paste the path to java in the following manner:

JAVA_HOME="path/to/jdk"

As I went with JDK 17, so I will be adding the following:

JAVA_HOME="/usr/lib/jvm/java-17-openjdk-amd64/bin/java"

Save changes and exit from the nano text editor.

Once you are done, reload the environment config file:

source /etc/environment

And if everything goes as planned, if you print the environment variable of JAVA_HOME then, it should give you the path you configured:

echo $JAVA_HOME

And there you have it!

Uninstall Java from Ubuntu

If you followed any of the discussed methods, you will find the Java uninstallation method for each one here.

To remove the JDK (default):

sudo apt remove default-jdk

To remove JRE (default):

sudo apt remove default-jre

To remove a specific version of JDK:

If you installed a specific version of JDK, you will need to execute the apt remove in the following syntax:

sudo apt remove openjdk-[version_no]-jdk

As I went with JDK 17, I will have to execute the following:

sudo apt remove openjdk-17-jdk

To remove a specific version of JRE:

If you installed a specific version of JRE, then, you will have to execute the apt remove in the following manner:

sudo apt remove openjdk-[version_no]-jre

As I installed JRE 17, I will be using the following command for removal:

sudo apt remove openjdk-17-jre

To remove the Oracle JDK

Removing deb packages requires a little effort but is still doable.

First, you will have to know the package name by which the Oracle JDK is installed:

apt list --installed | grep -w 'jdk\|local'

It will be installed locally and probably will be the first result:

In my case, the package name is jdk-17 as I installed JDK 17. Sure, yours can be different!

Once you identify the package name, all you have to do is execute the apt remove and append the package name to it:

sudo apt remove jdk-17

And that's it!

Want to learn how to run Java programs?

If you are just getting started in java programming and have no idea how to run the java program, we have a detailed guide on that topic:

How to Run Java Programs in Ubuntu

So, you have started learning Java programming? That’s good. And you want to run the java programs on your Linux system? Even better. Let me show how to run Java in terminal in Ubuntu and other Linux distributions. Running Java programs in Ubuntu Let’s go in proper steps

It's FOSSAbhishek Prakash

I hope this guide has solved how you can install java on Ubuntu.

And if you went through any errors while installation or have any other queries, let me know in the comments.