Install Java on Ubuntu 22.04: The Complete, Step-by-Step Guide

Want to run Java applications or develop Java software on your Ubuntu 22.04 server? This guide provides a comprehensive walkthrough on how to install Java on Ubuntu 22.04 using apt, even if you're a complete beginner. Learn how to install both the JRE (Java Runtime Environment) and JDK (Java Development Kit), including OpenJDK and Oracle JDK.

Why Install Java on Ubuntu?

Java is a versatile platform powering a vast ecosystem of applications. Installing Java lets you:

• Run popular software like Tomcat, Jenkins, and Cassandra.
• Develop your own Java applications.
• Utilize Java-based tools and libraries.

Prerequisites

• An Ubuntu 22.04 server, set up with a non-root user with sudo privileges and a firewall.

Step 1: Installing Java – Choose Your Flavor

You have two main choices when you install Java on Ubuntu: OpenJDK and Oracle JDK. Here's a quick breakdown:

• OpenJDK: An open-source implementation of Java.
• Oracle JDK: The official version from Oracle.

Both are standards-compliant, but licensing and support considerations might influence your decision.

Option 1: Quick & Easy – Install the Default JRE/JDK (OpenJDK)

Ubuntu 22.04 comes with OpenJDK 11, a fully open-source Java option. Here's how to get started:

1. Update your package list:

   sudo apt update
   

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2. Install the JRE (Java Runtime Environment): This lets you run Java applications.

   sudo apt install default-jre
   

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3. Verify the installation:

   java -version
   

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   You should see output confirming the OpenJDK version.

4. (Optional) Install the JDK (Java Development Kit): If you also need to develop Java applications, install the JDK. This will also install JRE.

   sudo apt install default-jdk
   

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5. Verify the JDK installation:

   javac -version
   

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   You should see output confirming the javac compiler version.

Option 2: Installing Oracle JDK 11

1. Create an Oracle Account: Since the Oracle agreement doesn’t allow automatic installation through the apt package, you will need an Oracle account to do this. Use this link to create one if you don't already have one.

2. Find the Correct Installer Version: Visit the oracle-java11-installer page to find out what the current software version is.

3. Download The Correct Version: Visit the Archive Downloads and locate the version that matches the software version you need.

4. Transfer the Downloaded File to Your Server: Use the scp command on your local machine to transfer the package to the home directory of your sammy user.

   scp Downloads/jdk-11.0.13_linux-x64_bin.tar.gz sammy@your_server_ip:~
   

5. Import the Signing Key:

   sudo gpg --homedir /tmp --no-default-keyring --keyring /usr/share/keyrings/oracle-jdk11-installer.gpg --keyserver keyserver.ubuntu.com --recv-keys EA8CACC073C3DB2A
   

6. Add the Repository to Your List of Package Sources:

   echo "deb [arch=amd64 signed-by=/usr/share/keyrings/oracle-jdk11-installer.gpg] https://ppa.launchpadcontent.net/linuxuprising/java/ubuntu jammy main" | sudo tee /etc/apt/sources.list.d/oracle-jdk11-installer.list > /dev/null
   

7. Update Your Package List:

   sudo apt update
   

8. Create the Following Directory:

   sudo mkdir -p /var/cache/oracle-jdk11-installer-local/
   

9. Move the Downloaded Package:

   sudo cp jdk-11.0.13_linux-x64_bin.tar.gz /var/cache/oracle-jdk11-installer-local/
   

10. Finally, install the package:

    sudo apt install oracle-java11-installer-local
    
    

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Step 2: Managing Java Versions with update-alternatives

If you have multiple Java installations, use update-alternatives to manage them:

1. Check installed versions:

   sudo update-alternatives --config java
   

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2. Select your default Java: Choose the number corresponding to your preferred Java version.

3. Repeat for other commands (optional): You can also configure javac, keytool, etc.

Step 3: Setting the JAVA_HOME Environment Variable

Many Java programs rely on the JAVA_HOME environment variable. Here's how to set it:

1. Determine your Java installation path: Use sudo update-alternatives --config java (as above) to find the path to your preferred Java installation.

2. Edit /etc/environment:

   sudo nano /etc/environment
   

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3. Add the JAVA_HOME variable: At the end of the file, add a line similar to this, replacing the example path with your actual path (without the bin/ part):

   JAVA_HOME="/usr/lib/jvm/java-11-openjdk-amd64"
   

4. Reload the environment:

   source /etc/environment
   

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5. Verify:

   echo $JAVA_HOME
   

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Conclusion

Congratulations! You've successfully installed Java on Ubuntu 22.04. You can now run Java applications and develop powerful Java software on your server. Remember to choose the right Java distribution (OpenJDK or Oracle JDK) based on your needs and licensing requirements.