OpenJDK 21 Download and Installation on Windows, macOS, Linux & Ubuntu

Quick guide to download and install OpenJDK 21 on Windows, macOS, and Linux.

1. What is OpenJDK?

OpenJDK is the open-source implementation of the Java Platform, Standard Edition (Java SE). It is free to use and provides a robust environment for developing Java applications.

2. Introduction to OpenJDK 21

OpenJDK 21 is the latest release of the open-source implementation of the Java Platform, Standard Edition (Java SE). It brings several new features, enhancements, and bug fixes to improve the performance, security, and functionality of the Java runtime environment.

3. Features of OpenJDK 21

OpenJDK 21 introduces several key features:

• Improved Performance
• Enhancements in JIT compiler optimizations.
• Reduced memory footprint and improved startup times.
• New Language Features
• Introduction of new language features like pattern matching for instanceof, sealed classes, and records.
• Security Enhancements
• Improved security with new cryptographic algorithms and security protocols.
• Other Notable Features
• Support for new platforms and architectures.
• Updated APIs and libraries.

4. System Requirements

Before installing OpenJDK 21, ensure that your system meets the following requirements:

• Operating System: Windows, macOS, Linux
• Disk Space: Minimum 200 MB
• RAM: Minimum 1 GB

5. Installation Guide

Follow the instructions below to install OpenJDK 21 on your operating system:

• Installing OpenJDK 21 on Windows
• Download the OpenJDK 21 distribution for Windows from the official website https://jdk.java.net/archive/
• Choose the suitable build from the list.
• Run the installer and follow the on-screen instructions.
• Set the JAVA_HOME environment variable.
• Installing OpenJDK 21 on macOS
• Use Homebrew to install OpenJDK 21:

brew install openjdk@21

• Set the JAVA_HOME environment variable.
• Installing OpenJDK 21 on Linux
• Install OpenJDK 21 using your distribution's package manager:
• Ubuntu/Debian:

sudo apt-get install openjdk-21-jdk

• CentOS/RHEL:

sudo yum install java-21-openjdk-devel

6. Setting Environment Variables

To set the JAVA_HOME environment variable:

• Windows:

set JAVA_HOME=C:\Path\to\your\OpenJDK-21
set PATH=%JAVA_HOME%\bin;%PATH%

• macOS/Linux:

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

7. Verifying the Installation

To verify that OpenJDK 21 is installed correctly, run the following command in your terminal or command prompt:

java -version

8. Updating OpenJDK 21

To update OpenJDK 21, download the latest version from the official website and reinstall it using the installation instructions provided above.

9. Conclusion

OpenJDK 21 offers significant improvements and new features that enhance the Java development experience. By following this guide, you can successfully install, configure, and use OpenJDK 21 on your system.

10. References

• Official OpenJDK Website: openjdk.java.net
• Oracle Java Documentation: docs.oracle.com/javase

11. OpenJDK Known Issues

Note: Here is the list of OpenJDK known issues OpenJDK Known Issues

Read Next:

• OpenJDK Developers Guide
• Redhat OpenJDK
• AdoptOpenJDK