This simple tutorial shows how to install the latest Oracle Java (JDK 21 so far) in Ubuntu Linux via the official binary package.

There used to be unofficial Ubuntu PPA to automate the process of installing Java JDK and setup the environment, however, discontinued. So, here’s the tutorial to manually install the Java package and set as default.

Install JDK 21 in Ubuntu:

Press Ctrl+Alt+T on keyboard to open a terminal window and follow the steps below one by one.

1. Download Java package

Firstly, go to oracle website and select download the .deb package:

It’s the 64-bit .deb package for modern PC and laptops, or tarball for ARM cpu architecture.

2. Install the .deb package

Once you downloaded the package, open terminal (Ctrl+Alt+T) and run the command below to install the deb package:

sudo apt install ~/Downloads/jdk-21_linux-x64_bin.deb

Here you may also double-click the .deb in file manager to install it via Ubuntu Software App.

For the ARM package (for Raspberry Pi, Apple M1/2, etc), run command to create ‘/usr/lib/jvm’ directory in case it does not exist:

sudo mkdir -p /usr/lib/jvm

Then, extract the tarball to that directory via:

sudo tar -zxf ~/Downloads/jdk-21_linux-aarch64_bin.tar.gz -C /usr/lib/jvm/

3. Set JDK 21 as default (for ARM only):

UPDATE: The .deb package now automatically set Java 21 as default! So, you ONLY need to follow the steps below for the ARM package.

It installs the files into ‘/usr/lib/jvm/jdk-21/‘ directory. To set it as default, do the following 2 steps one by one.

a.) Create symbolic links for the executable files:

sudo update-alternatives --install /usr/bin/java java /usr/lib/jvm/jdk-21/bin/java 1

sudo update-alternatives --install /usr/bin/javac javac /usr/lib/jvm/jdk-21/bin/javac 1

sudo update-alternatives --install /usr/bin/jar jar /usr/lib/jvm/jdk-21/bin/jar 1

Similarly, add links for other executable files (e.g., jarsigner, jlink, javadoc) as you need.

b.) Next, run the commands below one by one, and type number to select Java JDK 21 as default.

sudo update-alternatives --config java

sudo update-alternatives --config javac

sudo update-alternatives --config jar

When done, verify by running command in terminal:

java -version

javac -version

4. Set JAVA_HOME (for ARM only):

As well, you only need to do this for ARM package. If installed the .deb version, just verify JAVA HOME via the bottom command.

Option 1.) Set JAVA_HOME for current command console, that will work until you close it:

export JAVA_HOME=/usr/lib/jvm/jdk-21

setenv JAVA_HOME=/usr/lib/jvm/jdk-21

Option 2.) To make it permanent, create and edit config file via command:

sudo gedit /etc/profile.d/jdk.sh

Depends on your desktop environment, you may replace gedit with mousepad for XFCE, xed for Linux Mint, pluma for MATE, kate for KDE Plasma, gnome-text-editor for Ubuntu 23.04+.

then add following lines:

export J2SDKDIR=/usr/lib/jvm/jdk-21
export J2REDIR=/usr/lib/jvm/jdk-21
export PATH=$PATH:/usr/lib/jvm/jdk-21/bin:/usr/lib/jvm/jdk-21/db/bin
export JAVA_HOME=/usr/lib/jvm/jdk-21
export DERBY_HOME=/usr/lib/jvm/jdk-21/db

And create anther one for C shell:

sudo gedit /etc/profile.d/jdk.csh

add following lines and save it:

setenv J2SDKDIR /usr/lib/jvm/jdk-21
setenv J2REDIR /usr/lib/jvm/jdk-21
setenv PATH ${PATH}:/usr/lib/jvm/jdk-21/bin:/usr/lib/jvm/jdk-21/db/bin
setenv JAVA_HOME /usr/lib/jvm/jdk-21
setenv DERBY_HOME /usr/lib/jvm/jdk-21/db

Finally, change the permissions via command, and it should take place next time you log in.

sudo chmod +x /etc/profile.d/jdk.csh /etc/profile.d/jdk.sh

To verify JAVA HOME, run the command below in terminal at next login:

java -XshowSettings:properties -version

Uninstall Java JDK 21

To uninstall the Java package, open terminal (Ctrl+Alt+T) and run command:

sudo apt remove --autoremove jdk-21

For the ARM version, simply remove all the installed files, by running the commands below one by one:

• Remove the alternative links:

  sudo update-alternatives --remove java /usr/lib/jvm/jdk-21/bin/java

  sudo update-alternatives --remove javac /usr/lib/jvm/jdk-21/bin/javac

  sudo update-alternatives --remove jar /usr/lib/jvm/jdk-21/bin/jar

• Remove JDK installation files:

  sudo rm -R /usr/lib/jvm/jdk-21

• And remove JAVA HOME config files:

  sudo rm /etc/profile.d/jdk.sh

  sudo rm /etc/profile.d/jdk.csh