Metals unable to find Java 11 JDK

[PawanKartikS]

I've just installed the metals extension from VSCode's marketplace and opened a scala file. I immediately got this error -

Error: No suitable Java version found
Unable to find a Java 8 or Java 11 installation on this computer. To fix this problem, update the 'Java Home' setting to point to a Java 8 or Java 11 home directory or select a version to install automatically

I had JDK 14 installed but since metals explicitly mentioned JDK 11, I did go ahead and install it and configured the java.home property as

"java.home": "/usr/lib/jvm/java-11-openjdk-11.0.8.10-2.fc32.x86_64/"

which is in fact the correct path. Yet, the error persists.

OS: Fedora 32

[tgodzik]

Thanks for reporting! We do use an utility library for locating java home, but it might not work with all possible configuration unfortunately.

Could you try specifying java home in the settings? The exact settings is "metals.javaHome" : "path-to-home"

Also, are there any other messages in the metals output? There might be some more info there saying what else could be an issue.

[PawanKartikS]

That fixes it. I'm so sorry, not sure how I missed that configuration! Thanks!

[tgodzik]

Glad it helped! This probably means the message is not clear enough.

[bes1002t]

I tried different approaches and only the last one worked:

1. $JAVA_HOME (Support variables when resolving values in settings microsoft/vscode#2809)
2. /usr/bin/java (which is actually a symlink to /usr/bin/java -> /etc/alternatives/java -> /usr/lib/jvm/java-11-openjdk-11.0.9.11-0.fc31.x86_64/bin/java)
3. /usr/lib/jvm/java-11-openjdk-11.0.9.11-0.fc31.x86_64/

Why is /usr/bin/java/ not working? Is vscode not able to dissolve symlinks?

[tgodzik]

I think /usr/bin/java is only a symlink to the java binary, not actual path to java home.

$JAVA_HOME should work, although VS Code will most of the time be started without the JAVA_HOME env variable. You would most likely need to to start it from terminal to have it defined.

[pfernandez]

Glad it helped! This probably means the message is not clear enough.

I ran into the exact same confusion today: Saw the update the 'Java Home' setting, went to :CocConfig, typed ja... and chose java.config.

Since the warning message isn't clear enough, maybe consider simply looking for java.home when metals.javaHome is doesn't exist.

[tgodzik]

Good idea, changed it in scalameta/metals-vscode#644

[godenji]

I think /usr/bin/java is only a symlink to the java binary, not actual path to java home.

No, in most linux distros you'll see as @bes1002t points out, something like:

/usr/bin/java -> /etc/alternatives/java -> /usr/lib/jvm/java-18-openjdk-18.0.1.1.2-1.rolling.fc36.x86_64

Seems that vs code doesn't resolve symlinks, so your only option is to hard code the path, which is unfortunate.

[tgodzik]

How would using /usr/bin/java work if it was a symlink to a directory? Or do you mean something else?

We could possibly try to resolve the symlink and go up the directories to infer real java home, which might work. Would you mind raising it in VS Code repository scalameta/metals-vscode ?

[godenji]

How would using /usr/bin/java work if it was a symlink to a directory?

I was incorrect, it does of course link to the java binary.

If the path resolves to a file named "java", then yes, you could probably traverse up to find java home. That would be a nice set-it-and-forget-it option for Linux users.

[godenji]

Would you mind raising it in VS Code repository scalameta/metals-vscode ?

Done