How to Install OpenJDK in macOS

Java is one of the most popular programming languages, widely used for creating web, mobile, and desktop applications. OpenJDK is an open-source version of the Java Development Kit (JDK), which includes everything you need to build and run Java applications. It is a preferred choice for many developers due to its reliability and free availability.

If you are using macOS and need Java for your projects, OpenJDK provides a quick and efficient way to get started. This guide will help you install OpenJDK step-by-step and prepare your system for Java development or running Java-based programs.

Methods to Install OpenJDK in macOS

Here in this section we are going to explain two methods to install OpenJDK in macOS. So, explore both methods and choose which one you like.

Method 2: Manual Installation

• If you prefer not to use Homebrew, you can manually download and install OpenJDK from the official website:
• Go to the OpenJDK official website and download the desired version for macOS.
• Once downloaded, double-click the .tar.gz file to extract it.
• Move the extracted folder to /Library/Java/JavaVirtualMachines/ using the Terminal:

sudo mv jdk-21.jdk /Library/Java/JavaVirtualMachines/

• Verify the installation by checking the Java version:

java -version

Set the JAVA_HOME Environment Variable

• Open your shell configuration file:

nano ~/.zshrc

• Add the following line

export JAVA_HOME="/Library/Java/JavaVirtualMachines/jdk-21.jdk/Contents/Home"

• Save and close the file.
• Reload the configuration

source ~/.zshrc

• Verify the JAVA_HOME variable:

Method 1: Using Homebrew

Step 1: Check If Java Is Already Installed

• Before installing OpenJDK, check if Java is already installed on your macOS:
• Open the Terminal (press ⌘Command + Space, type Terminal, and hit Enter).
• Type the following command:

java -version

• If Java is installed, you will see the version number. If not, you will see a message saying Java is not installed.

Step 2: Install Homebrew (If Not Already Installed)

• Homebrew is a package manager for macOS that makes it easy to install software like OpenJDK. To check if Homebrew is installed, run:

brew --version

• If Homebrew is not installed, install it using this command:

/bin/bash -c "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/HEAD/install.sh)"

• Follow the on-screen instructions to complete the installation.

Step 3: Install OpenJDK

• Once Homebrew is installed, you can use it to install the latest version of OpenJDK:
• Open the Terminal run the following command:

brew install openjdk

• Homebrew will download and install the latest version of OpenJDK.

Step 4: Verify the Installation

• To confirm that OpenJDK has been installed successfully, check the version:

java -version

• You should see output showing the installed version of OpenJDK, such as:

openjdk version "21.0.1" 2025-01-01
OpenJDK Runtime Environment (build 21.0.1+12)
OpenJDK 64-Bit Server VM (build 21.0.1+12, mixed mode)

Step 5: Set JAVA_HOME (Optional)

• Some applications require the JAVA_HOME environment variable to be set. Here’s how you can set it:
• Open the Terminal and edit your shell configuration file. If you are using zsh (default shell on macOS), run:

nano ~/.zshrc

• Add the following line to the file:

export JAVA_HOME="$(brew --prefix openjdk)/libexec/openjdk.jdk/Contents/Home"

• Save the file (press Ctrl + O, then Enter, and Ctrl + X to exit).
• Apply the changes by running:

source ~/.zshrc

• Verify the JAVA_HOME variable:

echo $JAVA_HOME

• This should display the path to your OpenJDK installation.

Conclusion

Installing OpenJDK on macOS can be done using different methods. Using Homebrew is quick and easy, while manual installation gives you more control over the process. Setting the JAVA_HOME environment variable ensures that Java applications work correctly on your system. By following the steps above, you can set up OpenJDK for Java development or running Java applications.

What is OpenJDK?

OpenJDK (Open Java Development Kit) is a free and open-source implementation of the Java Platform, Standard Edition. It includes the tools necessary for developing and running Java applications.

What is Homebrew, and why should I use it?

Homebrew is a package manager for macOS that makes it easier to install and manage software. Using Homebrew to install OpenJDK is quicker and automatically handles dependencies.

How can I check if OpenJDK is already installed on my system?

Open the Terminal and type the following command:

java -version

If Java is installed, it will display the version number. Otherwise, you will see a message saying Java is not installed.

Can I install multiple versions of OpenJDK on macOS?

Yes, you can install multiple versions of OpenJDK. To manage and switch between them, you can use tools like jEnv or manually set the JAVA_HOME variable to point to the desired version.

Is OpenJDK suitable for production use?

Yes, OpenJDK is widely used in both development and production environments. If you need a long-term support version for production, consider installing an LTS release like OpenJDK 17 or OpenJDK 11.