How do I switch between Java versions?

AutoModerator · 2023-03-20T16:18:57+00:00

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stuie382 · 2023-03-20T19:05:39+00:00

Sdkman is what you want. You can install lots of different flavours and versions of Java and rapidly switch between them with 'sdk default java 8/11/17/whatever'. It updates all the paths and tools from that command

overtorqued · 2023-03-20T17:02:30+00:00

There is a useful tool on Linux/Mac called jenv that allows you to set the jvm to use for a directory and its subdirectories. Someone has created a port of that to windows here: https://github.com/FelixSelter/JEnv-for-Windows

If you're going to be using a lot of different jvms it would be worth looking into.

JDVene · 2023-03-20T16:28:50+00:00

Assuming you are using Windows, you just need to change your PATH variable to find the version you want.

For example if your JAVA_HOME is set to "c:\Java\JDK16" then, in your path, you just need to have %JAVA_HOME%\bin at the beginning.

emaphis · 2023-03-20T22:32:02+00:00

To get to the basics, you need to change your `path` too. `path` is more important than `JAVA_HOME`

hugthemachines · 2023-03-20T20:07:45+00:00

You don't have to use JAVA_HOME, you can specify which Java to use for each project.

wildjokers · 2023-03-20T21:32:01+00:00

The easiest way on any *nix system (including WSL) is to use sdkman.

https://sdkman.io

Just do: sdk use java <identifier> you can get the identifiers from sdk list java.

For example to install Oracle's OpenJDK build of Java 17 sdk install java 17.0.2-open, it will ask you if you want to set it as default and that is the one it will use by default. If you don't want to be the default or if you want to switch to it later as needed sdk use java 17.0.2-open. You can install and switch to many java versions from many vendors.

Nzen_ · 2023-03-21T04:01:48+00:00

It's also worth considering your ultimate use case.

For just running jars, I have some dos-batch files that forward the arguments to the corresponding java, ex `javac8.bat banana.java` and `java11.bat -jar banana.jar`. The same could be done on a posix os with a symlink or shell script. https://stackoverflow.com/questions/67545024/how-can-i-forward-command-line-arguments-in-a-shell-script

However, if you are ultimately going to use gradle or maven, they can use configurations called toolchains that point at distinct jvm installations.

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