How to Install Java on Ubuntu 26.04

Many server applications, build tools, and IDEs will not start until Java is installed. Ubuntu 26.04 ships OpenJDK 25 as its default Java, and the same repositories carry older and newer OpenJDK releases for applications that need a specific version.

This guide explains how to install OpenJDK and Oracle JDK on Ubuntu 26.04, switch between installed versions, and set the JAVA_HOME environment variable.

Quick Reference #

Before You Begin #

There are several Java implementations available. OpenJDK and Oracle JDK are the two most common choices. OpenJDK is the default option in Ubuntu and the best fit for most systems.

Ubuntu 26.04 includes OpenJDK packages for both the Java Runtime Environment (JRE) and the Java Development Kit (JDK). The JRE includes the Java virtual machine (JVM) and the libraries needed to run Java programs. The JDK includes the JRE plus the tools needed to build Java applications.

The Ubuntu 26.04 repositories provide OpenJDK 8, 11, 17, 21, 25, and 26. Java 25 is the default version and comes from the Main repository. The other versions are in the Universe repository.

If you are not sure which package to install, start with the default OpenJDK version. Some applications require a specific Java release, so check the application documentation before you install it.

Installing OpenJDK in Ubuntu #

Check if Java is already installed:

java -version

If Java is not installed, the output will tell you the command is not found. Otherwise, it shows the installed version.

Update the package index:

sudo apt update

Java 25 is the latest long-term support (LTS) release and the default Java in Ubuntu 26.04. The default-jdk package installs the same version.

To install OpenJDK 25, run:

sudo apt install openjdk-25-jdk

Verify the installation:

java -version

openjdk version "25.0.4.1" 2026-08-18
OpenJDK Runtime Environment (build 25.0.4.1+1-1-26.04.4-Ubuntu)
OpenJDK 64-Bit Server VM (build 25.0.4.1+1-1-26.04.4-Ubuntu, mixed mode, sharing)

The first line shows the Java version and its release date. The Ubuntu suffix in the build string tells you the JDK came from the Ubuntu repositories.

JRE is included in the JDK package. If you need only JRE, install the openjdk-25-jre package. For a minimal Java runtime without graphical dependencies, install the openjdk-25-jre-headless package.

Installing Oracle Java in Ubuntu #

Oracle JDK is not available in the default Ubuntu repositories. You can install it by downloading the .deb package from Oracle.

At the time of writing, Oracle’s downloads page offers JDK 27, the latest feature release, and JDK 25, the latest LTS release. Both are available under the Oracle No-Fee Terms and Conditions (NFTC), which allows free production use and redistribution. JDK 25 receives NFTC updates until September 2028. JDK 27 receives them only until March 2027, when JDK 28 replaces it. If you plan to standardize on Oracle JDK, review Oracle’s current licensing terms before deployment.

Visit the Oracle Java Downloads page and select the version you need.

In this example, we will download and install Java 25 because it is the current LTS release. Choose the Linux x64 Debian Package for the version you want and download the .deb file.

These Oracle package instructions require an amd64 (x86-64) system. Oracle does not provide an ARM64 .deb package. On ARM64 systems, use OpenJDK from the Ubuntu repositories or follow Oracle’s archive installation instructions for its Linux ARM64 .tar.gz download.

If you are installing on a server, use wget to download the file:

wget https://download.oracle.com/java/25/latest/jdk-25_linux-x64_bin.deb

For JDK 27, replace 25 with 27 in both the URL and the filename.

Install the package:

sudo apt install ./jdk-25_linux-x64_bin.deb

Replace the filename if you downloaded a different version.

The package installs the JDK under /usr/lib/jvm/, in a directory named after the full release number, such as jdk-25.0.5.0.3-oracle-x64.

Setting the Default Java Version #

If you have multiple Java versions installed, check the current default:

java -version

In automatic mode, the installed version with the highest priority becomes the default. Oracle JDK registers a much higher priority than OpenJDK, so installing it switches the default to Oracle JDK. If you selected a version manually, your choice is kept.

Change the default version with update-alternatives:

sudo update-alternatives --config java

You will see a list of installed Java versions:

There are 2 choices for the alternative java (providing /usr/bin/java).

  Selection    Path                                             Priority   Status
------------------------------------------------------------
* 0            /usr/lib/jvm/jdk-25.0.5.0.3-oracle-x64/bin/java   419471408 auto mode
  1            /usr/lib/jvm/java-25-openjdk-amd64/bin/java       2511      manual mode
  2            /usr/lib/jvm/jdk-25.0.5.0.3-oracle-x64/bin/java   419471408 manual mode

Press <enter> to keep the current choice[*], or type selection number:

The * marks the current default. Selection 0 follows the highest priority automatically, and selections 1 and 2 pin a specific JDK in manual mode.

Enter the number of the version you want as default and press Enter.

The Java compiler has its own alternative. To switch javac to the same JDK, run:

sudo update-alternatives --config javac

Verify that the runtime and the compiler use the version you selected:

java -version
javac -version

Setting the JAVA_HOME Environment Variable #

Some Java applications use the JAVA_HOME environment variable to determine the JDK location.

First, find the Java installation path:

sudo update-alternatives --config java

The paths are:

• Oracle JDK 25 is located at /usr/lib/jvm/jdk-25.0.5.0.3-oracle-x64/bin/java
• OpenJDK 25 is located at /usr/lib/jvm/java-25-openjdk-amd64/bin/java

Open the /etc/environment file:

sudo nano /etc/environment

Add the following line (adjust the path for your preferred version):

JAVA_HOME="/usr/lib/jvm/java-25-openjdk-amd64"

Sourcing the file sets the variable in your current shell, but it does not export it. Programs started from the shell, such as Maven or Gradle, will not see it until you export it:

source /etc/environment
export JAVA_HOME

Verify the variable is exported:

printenv JAVA_HOME

/usr/lib/jvm/java-25-openjdk-amd64

Other login sessions pick up the new setting after you sign out and sign back in.

Uninstalling Java #

OpenJDK is split across several packages. Removing only openjdk-25-jdk leaves the runtime and headless development tools installed. To remove OpenJDK 25, remove both headless packages; apt also removes the JDK and JRE packages that depend on them.

Check the proposed removals first, especially if other applications depend on Java:

apt --simulate remove openjdk-25-jdk-headless openjdk-25-jre-headless

If the removal list is correct, run:

sudo apt remove openjdk-25-jdk-headless openjdk-25-jre-headless

Replace 25 in both package names with the version you want to remove.

Oracle JDK is installed as the jdk-25 package. To remove it, run:

sudo apt remove jdk-25

For Oracle JDK 27, the package name is jdk-27.

Conclusion #

OpenJDK 25 from the Ubuntu repositories works for most applications on Ubuntu 26.04 and receives updates through apt. Install Oracle JDK when a vendor requires it, and set JAVA_HOME explicitly when a project pins a specific Java version.

To check which Java version a system is running, see our guide on how to check the Java version .

About the authors

Dejan Panovski

Dejan Panovski is the founder of Linuxize, an RHCSA-certified Linux system administrator and DevOps engineer based in Skopje, Macedonia. Author of 1000+ Linux tutorials with 20+ years of experience turning complex Linux tasks into clear, reliable guides.

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