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Custom JDK Versions Per Project With SDKMAN!
For more information about installing and using SDKMAN!, check out my article - Managing JDK Versions With SDKMAN!
Before we can start using the sdk env command, we must first ensure we are using the latest version of SDKMAN! The software can be updated by using the sdk selfupdate command
% sdk selfupdate
No update available at this time.SDKMAN! uses a hidden file called .sdkmanrc which contains a parameter specifying which JDK version to use for a project. To configure and use this file is a simple 3 step process.
1 Create the .sdkmanrc file. This can easily be created by navigating to the required directory and executing sdk env init
% sdk env init
.sdkmanrc created.2 Configure the version. Once we've created the file, edit it and add a line java=x.x.x.x specifying the version of Java to use. For example to use Adopt Open JDK version 11, the file would look like:
% cat .sdkman
java=11.0.2.hs-adpt3 Initialize the environment. After editing the .sdkmanrc fille, we can configure the environment by executing the sdk env command.
% sdk env
Using java version 11.0.2-open in this shell.
%
% java -version
openjdk version "11.0.2" 2019-01-15
OpenJDK Runtime Environment 18.9 (build 11.0.2+9)
OpenJDK 64-Bit Server VM 18.9 (build 11.0.2+9, mixed modeFinally, we can get SDKMAN! to automatically change JDK to the version defined within .sdkmanrc by changing configuration. To do this, edit the ~/.sdkman/etc/config file and add/edit the property sdkman_auto_env=true. This will probably already exist and be set to false, so make sure you edit this setting if it is there rather than duplicating it.
Now, whenever you change into a directory containing a .sdkmanrc file in it, the JDK will automatically be changed to your desired version. Fantastic !
% cd project1
Using java version 11.0.2-open in this shell.
%
% cd project2
Using java version 14.0.1-open in this shell.Photo by Octavian Dan on Unsplash
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