Java, a cornerstone for countless applications and enterprise systems, remains a vital programming language. For developers and system administrators working with Ubuntu 24.04, setting up a Java Development Kit (JDK) is often one of the first steps. This guide will walk you through installing OpenJDK, the open-source implementation of the Java Platform, Standard Edition, on your Ubuntu 24.04 system.
Before proceeding with any installation, it’s always a good practice to update your package list to ensure you’re working with the latest available information. Open your terminal and execute:
“`bash
sudo apt update
sudo apt upgrade -y
“`
Ubuntu 24.04 repositories typically contain several versions of OpenJDK. To see which versions are available, you can use the following command:
“`bash
sudo apt search openjdk
“`
This will list packages like `openjdk-11-jdk`, `openjdk-17-jdk`, `openjdk-21-jdk`, etc. For modern development, OpenJDK 17 (LTS) or OpenJDK 21 (LTS) are popular choices. Let’s assume you want to install OpenJDK 17.
To install OpenJDK 17, use the following command:
“`bash
sudo apt install openjdk-17-jdk -y
“`
If you prefer OpenJDK 21, simply replace `openjdk-17-jdk` with `openjdk-21-jdk`.
After the installation completes, you can verify the Java version installed on your system:
“`bash
java -version
“`
You should see output similar to:
“`
openjdk version “17.0.x” 202x-xx-xx
OpenJDK Runtime Environment (build 17.0.x+x-Ubuntu-1ubuntu2)
OpenJDK 64-Bit Server VM (build 17.0.x+x-Ubuntu-1ubuntu2, mixed mode, sharing)
“`
If you have multiple Java versions installed, you might want to set a default one. Ubuntu provides a mechanism for this using the `update-alternatives` command. First, list the installed Java alternatives:
“`bash
sudo update-alternatives –config java
“`
You will see a list of available Java installations with a number next to each. Enter the number corresponding to the version you wish to set as default and press Enter.
To set the `JAVA_HOME` environment variable, which is often required by Java applications, you need to find the installation path of your chosen JDK. For OpenJDK, it’s typically located in `/usr/lib/jvm/`. You can find the exact path using:
“`bash
sudo update-alternatives –query java
“`
Look for the “Value” line. For example, it might be `/usr/lib/jvm/java-17-openjdk-amd64/bin/java`. The `JAVA_HOME` path would be `/usr/lib/jvm/java-17-openjdk-amd64`.
Now, open your shell’s profile file (e.g., `~/.bashrc` or `~/.profile` for Bash, `~/.zshrc` for Zsh) with a text editor:
“`bash
nano ~/.bashrc
“`
Add the following lines to the end of the file, replacing the path with your actual `JAVA_HOME` path:
“`bash
export JAVA_HOME=”/usr/lib/jvm/java-17-openjdk-amd64″
export PATH=$PATH:$JAVA_HOME/bin
“`
Save the file (Ctrl+O, Enter) and exit (Ctrl+X). Then, apply the changes:
“`bash
source ~/.bashrc
“`
You can verify `JAVA_HOME` is set correctly:
“`bash
echo $JAVA_HOME
“`
With Java (OpenJDK) successfully installed and configured, your Ubuntu 24.04 system is ready to run and develop Java applications.
