AdoptOpenJDK Open for Business

Before downloading a JDK from Oracle, you need to know two things. (1) You can't use that software in production without a paid license from Oracle (2) You can only get the current six-month release, not the long-term-support release there. For many users, the OpenJDK from http://adoptopenjdk.net is a better option. However, those downloads don't come with an installer. Here I provide simple installation instructions for Windows, Mac OS, and Linux.

As of JDK 11, the usage rules for the Oracle JDK are complex. However, there is a free alternative: OpenJDK. There is no functional difference between the Oracle JDK and OpenJDK. If you want to learn or teach Java, or develop software with Java, I suggest that you go with OpenJDK unless you have a specific business reason to use the Oracle JDK.

The AdoptOpenJDK foundation has committed to providing builds that integrate security fixes well beyond Oracle's six month window. Those builds don't come with installers, but it is easy enough to do the installation with a small amount of command-line fu.

Here is my set of instructions that are optimized for simplicity, predictability, and transparency.

Windows 10

• Using the Microsoft Edge browser, visit https://adoptopenjdk.net, select “OpenJDK 11 with Hotspot” and click the Latest Release button. If you are asked what you want to do with the file, select “Save”.



• Wait until the download and security scan is finished. The security scan can take a very long time—it's a Windows thing. When it is complete, you get an option “Open Folder”.

  

  In the file explorer window, locate the Downloads directory and the file that you just downloaded—it will have a name starting with OpenJDK11-jdk_x64_windows_hotspot_11. Right-click and select “Extract All”.

  

  As extraction target, specify C:\Users\your user name. In fact, you will be given a suggestion that starts with this folder—just erase everything after your user name.

  

  The extraction can take a very long time—it's a Windows thing.

  

  Wait for the process to finish.
• Open a command shell by holding down the Windows and R keys together, then typing cmd, and hitting Enter.

  

  Then paste the following commands:

  rd /s /q jdk-11
  move jdk-11* jdk-11

  If the first command gives an error “The system cannot find the file specified”, that's ok—it simply means you didn't have a prior version.
• Test that all works well:

  jdk-11\bin\java --version
  

  

  You should get a response such as

  openjdk 11 2018-09-25
  OpenJDK Runtime Environment AdoptOpenJDK (build 11+28)
  OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11+28, mixed mode)

• Make this selection permanent:

  setx PATH "%HOMEDRIVE%%HOMEPATH%\jdk-11\bin;%PATH%"
  

• Open a new terminal and try that this works:

  java

  You should get the same response as before.

  

• If the preceding step gave you a different version of Java, that means that you still have an old version of Java installed. First, open the Settings menu by holding the Windows + I keys together. Go to Apps and find any Java versions. Uninstall them. Now open a new terminal and try the java command again.
• If the preceding step gave you an error message, then you may have been unlucky and run into a situation where the Oracle Java uninstaller didn't clean up properly. In that case, you need to manually clean up the system environment variables. Hold down the Windows + R keys and type control into the run dialog. Then hit Ctrl + Shift + Enter together to run as an administrator. Agree to running the control panel as administrator. Select System and Security → System → Advanced system settings → Environment Variables. In the System variables area, select PATH and click Edit. Then select any lines related to Java and hit Delete. Click Ok to close the open dialogs. Now open a new terminal and try the java command again.
• When installing an IDE, tell it that your Java development environment is in c:\Users\your user name\jdk-11. Some installers want to see the bin folder or a specific file inside it. For example, Eclipse wants the javaw.exe file inside the bin folder.

  

  

Mac OS

• Visit https://adoptopenjdk.net and prepare to download the OpenJDK with Hotspot for Mac OS.
• Now download the file by right-clicking on the download button and choosing the “Save link as” option.

  

  The file name will be something like OpenJDK11-jdk_x64_mac_hotspot_11_28.tar.gz. Save the file to the Download directory.
• When the download is complete, issue the following commands in a terminal window. This will uncompress the archive into your home directory.

tar xf Downloads/OpenJDK11*.tar.gz

• Now move the directory where MacOS X expects it. You will be asked to provide your administrator password.

  sudo rm -rf /Library/Java/JavaVirtualMachines/jdk-11
  sudo mv jdk-11+* /Library/Java/JavaVirtualMachines/jdk-11
  

• Test that all works well:

  $(/usr/libexec/java_home -v 11)/bin/java --version
  

  You should get a response such as

  openjdk 11 2018-09-25
  OpenJDK Runtime Environment AdoptOpenJDK (build 11+28)
  OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11+28, mixed mode)

• Make this selection permanent:

  echo "PATH=\$(/usr/libexec/java_home -v 11)/bin:\$PATH" >> .bash_profile
  

• Open a new terminal and try that this works:

  java

  You should get the same response as before.

Linux

• Before downloading, open a terminal and remove any prior downloads. Open a terminal window and issue these commands:

  rm -f Downloads/OpenJDK11*.tar.gz
  

• Visit https://adoptopenjdk.net and select “OpenJDK 11 with Hotspot” and click on the “Latest Release” button. Select the Linux 64 platform. Right-click the Download button and choose the “Save link as” otption.

  

  Select the Download directory as the target. When the download is complete, uncompress the archive into your home directory. Issue this command in the same terminal window that you opened previously.

tar xf Downloads/OpenJDK11*.tar.gz

• Remove any prior jdk-11 directory and rename the directory to jdk-11:

  rm -rf jdk-11
  mv jdk-11+* jdk-11
  

• Test that all works well:

  jdk-11/bin/java --version
  

  You should get a response such as

  openjdk 11 2018-09-25
  OpenJDK Runtime Environment AdoptOpenJDK (build 11+28)
  OpenJDK 64-Bit Server VM AdoptOpenJDK (build 11+28, mixed mode)

• Make this selection permanent:

  echo "PATH=$(pwd)/jdk-11/bin:\$PATH" >> .bashrc
  

  

• Open a new terminal and try that this works:

  java

  You should get the same response as before.