Install Java on Linux
Step by Step Instructions

In this guide, we’ll walk you through how to install Java on any major Linux distribution.

We will cover

• How to check if Java is already installed
• Installing OpenJDK via package manager
• Installing Oracle JDK manually
• Setting JAVA_HOME and updating PATH
• Verifying installation with Java programs

Step 1: Check if Java is Already Installed

Before you install anything, it's good practice to check whether Java is already on your system.

java -version

Command 'java' not found, but can be installed with:
sudo apt install default-jre

If you see something like the above message, Java isn’t currently installed. If Java is installed, you'll see an output like this:

openjdk version "17.0.8" 2023-07-18
OpenJDK Runtime Environment (build 17.0.8+7-Ubuntu-222.04)
OpenJDK 64-Bit Server VM (build 17.0.8+7-Ubuntu-222.04, mixed mode, sharing)

Step 2: Install OpenJDK (Recommended for Most Users)

OpenJDK is the open-source implementation of Java. It is stable, secure, and available directly through most Linux package managers.

Open a terminal and run the following commands based on your Linux distribution.

For Ubuntu/Debian:

sudo apt update
sudo apt install default-jdk

For Fedora:

sudo dnf install java-17-openjdk-devel

For Arch Linux:

sudo pacman -S jdk-openjdk

After installation, confirm the Java version:

java -version

openjdk version "17.0.8" 2023-07-18

Step 3: Install Oracle JDK (Optional)

If your project specifically requires Oracle JDK, you can download and install it manually. Oracle JDK includes some commercial features and licensing considerations.

Download and Extract Oracle JDK

Go to the official Oracle JDK downloads page and download the appropriate version for Linux. Then run:

cd ~/Downloads
tar -xvf jdk-21_linux-x64_bin.tar.gz
sudo mv jdk-21 /usr/lib/jvm/jdk-21

Configure Oracle JDK as Default

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

Step 4: Set JAVA_HOME and Update PATH

It's important to let your system know where Java is located. To do this, follow these steps:

1. Open the terminal and edit the shell configuration file

Use any text editor to open your shell configuration file. Use the command based on your shell:

For bash users:

nano ~/.bashrc

For zsh users:

nano ~/.zshrc

2. Add the following lines at the end of the file:

export JAVA_HOME=/usr/lib/jvm/jdk-21
export PATH=$JAVA_HOME/bin:$PATH

3. Save and close the file

In nano, press Ctrl + O to save, then Ctrl + X to exit.

4. Apply the changes

Run the following command to apply the changes immediately:

For bash users:

source ~/.bashrc

For zsh users:

source ~/.zshrc

Step 5: Test Java Installation

Let’s test our installation with a simple Hello World program:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello, Java on Linux!");
    }
}

Compile:

javac HelloWorld.java

Run:

java HelloWorld

Hello, Java on Linux!

If you see this output, your Java installation is working perfectly!

Final Thoughts

For most developers, OpenJDK is sufficient and easily manageable through package managers. However, if you’re working in an enterprise setting where Oracle JDK is mandatory, manual installation offers full control.

Now that Java is ready to go, you can begin building Java applications.