Managing multiple jdk versions using sdkman

It is a common use-case to have multiple versions of various tools installed on your computer. Notable examples are different JDK versions or gradle. For a long time I installed them manually and added aliases to my shell configuration like that:

alias gradle48="~/bin/gradle-4.8.1/bin/gradle"

This works well for tools like gradle, but installing and maintaining multiple JDK versions was always a bit of a pain. Recently I found a very neat and amazing solution to this problem: sdkman.

It is a small tool that manages multiple versions of development kits on your computer. Installation is very easy:

$ curl -s "https://get.sdkman.io" | bash

and afterwards add something like this to your .bashrc or respective profile script:

[[ -s "~/.sdkman/bin/sdkman-init.sh" ]] && source "~/.sdkman/bin/sdkman-init.sh"

Now you should be able to use the sdk command to install different SDKs or change the current version in use:

sdk list java

will print something like this:

================================================================================\n
Available Java Versions
================================================================================
 Vendor        | Use | Version      | Dist    | Status     | Identifier
--------------------------------------------------------------------------------
 AdoptOpenJDK  |     | 14.0.0.j9    | adpt    |            | 14.0.0.j9-adpt      
               |     | 14.0.0.hs    | adpt    |            | 14.0.0.hs-adpt      
               |     | 13.0.2.j9    | adpt    |            | 13.0.2.j9-adpt      
               |     | 13.0.2.hs    | adpt    |            | 13.0.2.hs-adpt      
               |     | 12.0.2.j9    | adpt    |            | 12.0.2.j9-adpt      
               |     | 12.0.2.hs    | adpt    |            | 12.0.2.hs-adpt      
               |     | 11.0.6.j9    | adpt    |            | 11.0.6.j9-adpt      
               |     | 11.0.6.hs    | adpt    | installed  | 11.0.6.hs-adpt      
               |     | 8.0.242.j9   | adpt    | installed  | 8.0.242.j9-adpt     
               | >>> | 8.0.242.hs   | adpt    | installed  | 8.0.242.hs-adpt     
...

You can see that I have installed different JDK versions and version 8.0.242.hs-adpt is currently the default. To switch to another version by default you can use for example sdk use java 11.0.6.hs-adpt.

Its an amazing tool and I can recommand it for anyone using a unix-based workstation.

Note: in case you are wondering about the suffixes: hs and j9. They refer to the actual JVM in use:

• good old Hotspot
• OpenJ9

The suffix fx indicates whether the JDK comes pre-packages with the JavaFX / OpenJFX toolkit (which is not part of the Oracle / OpenJDK distributions anymore).