To replace JDK 1.8 with OpenJDK 11 on Windows, you must first completely uninstall the existing Java Development Kit through the Control Panel or Settings app to prevent path conflicts. Next, download the OpenJDK 11 distribution from a trusted provider like Eclipse Temurin and extract it to a dedicated directory. Finally, update your system's PATH environment variable to point to the new
bin folder and verify the installation using the command line.
Uninstalling JDK 1.8
Before installing a new version of Java, it is crucial to remove the old one. Having multiple versions installed can lead to confusing errors where your application inadvertently uses the wrong runtime. The most reliable method to ensure a clean slate is to use the Windows built-in uninstaller.
Open the Start menu and type "Add or remove programs" to access the system settings. Scroll through the list of installed applications until you find entries related to Oracle Java or OpenJDK 1.8. You may see multiple entries such as "Java SE Development Kit 1.8 Update XXX" and "Java SE Runtime Environment." Select each relevant entry and click the "Uninstall" button. Follow the on-screen prompts to complete the removal process.
After the uninstallation finishes, restart your computer. This step ensures that any lingering file locks are released and that the operating system clears references to the old Java paths. While not strictly mandatory in every case, a reboot significantly reduces the risk of residual configuration issues affecting the new installation.
Downloading OpenJDK 11
With the old version removed, you need to acquire the new runtime. OpenJDK is an open-source implementation of the Java Platform, Standard Edition. For Windows users, the Eclipse Temurin build is highly recommended due to its stability and long-term support.
Navigate to the official Eclipse Adoptium website. Look for the latest release of the Temurin 11 distribution. Ensure you select the correct architecture for your system, which is typically x64 for modern 64-bit Windows machines. Download the ZIP archive rather than the MSI installer if you prefer manual control over the installation directory. The ZIP file allows you to place the JDK anywhere on your drive, making it easier to manage multiple versions in the future if needed.
Once the download completes, locate the file in your Downloads folder. Right-click the archive and choose "Extract All..." to unzip the contents. It is best practice to move this extracted folder to a permanent location, such as
C:\Program Files\Java\jdk-11.0.x, to keep your root directories organized. Avoid extracting directly into folders with spaces in their names, as this can sometimes cause issues with older build tools.
Configuring Environment Variables
The final and most critical step is telling Windows where to find the new Java executable. If you do not update the PATH variable, commands like
java and
javac will fail with "command not found" errors.
Right-click the Start button and select "System" or navigate to Settings > System > About. On the right side (or bottom), click "Advanced system settings." In the System Properties window, click the "Environment Variables..." button at the bottom. Under the "System variables" section, scroll down to find the variable named
Path. Select it and click "Edit."
In the Edit Environment Variable window, click "New" and add the path to the
bin directory of your newly installed OpenJDK. For example:
C:\Program Files\Java\jdk-11.0.x\bin. If you have other Java installations, ensure this new path appears before any others in the list, or simply remove old Java paths entirely to avoid ambiguity. Click "OK" on all open dialogs to save your changes.
It is important to note that any previously opened Command Prompt or PowerShell windows will not see these changes immediately. You must close and reopen them to load the updated environment variables.
Verifying the Installation
Now that the setup is complete, you should verify that everything is working correctly. Open a new Command Prompt window by searching for "cmd" in the Start menu. Type the following command and press Enter:
java -version
You should see output indicating that the version is 11.x.x, confirming that the system is now using OpenJDK 11. Additionally, check the compiler by typing:
javac -version
This should also return version 11.x.x. If both commands return the expected version numbers, your migration from JDK 1.8 to OpenJDK 11 is successful. Your Java applications should now compile and run against the newer standard. For more details on ensuring optimal performance with specific library configurations, you might want to check
Ensuring Temurin OpenJDK Uses Static Libraries: A Step-by-Step Guide.
Frequently Asked Questions
Will my existing Java projects still work?
Most projects written for JDK 1.8 will continue to work because OpenJDK 11 maintains backward compatibility for legacy code. However, some deprecated APIs removed in later versions may cause compilation errors, so you should test your specific application thoroughly after the switch.
Can I keep both JDK 1.8 and OpenJDK 11 installed?
Yes, you can install multiple versions side-by-side without conflict. To switch between them, you simply change the
JAVA_HOME variable or modify the
Path entry order depending on which version you want to be the default for your current session.
What if the java command is still not found?
If you receive a "command not found" error, verify that you restarted your terminal after changing the environment variables. Also, double-check that the path in your system settings exactly matches the location of the
bin folder in your extraction directory, including any typos in the folder name.
Is OpenJDK 11 secure enough for production?
OpenJDK 11 is a Long Term Support (LTS) release and receives regular security updates from distributions like Eclipse Temurin. It is considered safe for production environments, provided you keep your JDK version updated to patch any newly discovered vulnerabilities.
How do I set JAVA_HOME specifically?
In the Environment Variables window, click "New" under System variables. Name the variable
JAVA_HOME and set its value to the root directory of your OpenJDK installation, such as
C:\Program Files\Java\jdk-11.0.x. Do not include the
\bin subdirectory in this specific variable.