How do I set up a custom JDK build in sdkman?-CodePudding

I was able to play around with the latest early access binary for Project Loom by downloading the file from http://jdk.java.net/loom/, extracting it (I had a directory called jdk-18), setting the JAVA_HOME env var to the jdk-18 directory, and adding the bin subdirectory for the build to the beginning of my PATH env var. I was able to use the build to compile and run a Java program using the virtual thread preview features.

But this feels like a very manual process. I like how SDKMAN manages JDKs on my system. How can I set up this early access build (or any other JDK build for that matter) as an entry in the list of JDKs managed by SDKMAN, so that I could change to it, for example, by typing sdk default java <my-jdk-18-name>?

CodePudding user response：

Joggling PATH variable for managing mulptiple JDK's was the only straightforward way of doing things for many years, however general automation of this process slowly improves.

Currently on I use jenv, generally any POSIX OS should be supported, I use it on Mac (brew install jenv).

Its main drawback for me — if you include its init $(jenv init -) in terminal RC script, it will delay terminal start-up for a few seconds.

Switch for particular folder would look like: jenv local <my-custom-jdk-name>

CodePudding user response：

SDKMAN has a feature called "Install Local Version(s)" (https://sdkman.io/usage#localversion).

So, to set up a custom build of the JDK with SDKMAN, I can download and install the JDK wherever I want and then link it to SDKMAN so that it's useable like any other JDK managed by SDKMAN:

wget https://download.java.net/java/early_access/loom/7/openjdk-18-loom 7-288_linux-x64_bin.tar.gz
tar -xf openjdk-18-loom 7-288_linux-x64_bin.tar.gz
mv jdk-18/ 18-loom
sdk install java 18-loom $(realpath 18-loom/)

After installing and linking:

~/javas > sdk default java 18-loom

Default java version set to 18-loom
~/javas > which java
/home/matt/.sdkman/candidates/java/current/bin/java
~/javas > java --version
openjdk 18-loom 2022-03-15
OpenJDK Runtime Environment (build 18-loom 7-288)
OpenJDK 64-Bit Server VM (build 18-loom 7-288, mixed mode, sharing)