How to pass JVM options

[thejeshgn]

While running a jar using jbang, I want to add --add-opens java.base/java.lang=ALL-UNNAMED as an option for JVM. How do I do that?

[thejeshgn]

I see that it has been under discussion here #418

[quintesse]

Hi @thejeshgn . Aren't those options always needed? In that case you could simply add //JAVAC_OPTIONS or //JAVA_OPTIONS to your source file. See https://www.jbang.dev/documentation/guide/latest/running.html#java-and-javac-options

[quintesse]

Sorry, I see now that you say jar so there's no source file to add options to.
In that case you can set the JBANG_JAVA_OPTIONS, like this: JBANG_JAVA_OPTIONS=--add-opens java.base/java.lang=ALL-UNNAMED jbang myjar.jar

[quintesse]

Dammit, that's also not right. Let me think some more before replying 😅

[quintesse]

So in the latest version of Jbang there is at least a way to do it. You can create an alias to refer to your jar, and that alias can have options that it will pass to the JVM at runtime, eg like this: jbang alias add --runopt="--add-opens java.base/java.lang=ALL-UNNAMED" myjar.jar

Btw @maxandersen , that's probably weird that we can do that in an alias but not on the command line, right? Perhaps we should at least add that --runopt flag to jbang run as well. And then perhaps a --buildopt as well? Wdyt?

[thejeshgn]

@quintesse Thank you.

I am using version 0.78.0 and jbang alias add --runopt="--add-opens java.base/java.lang=ALL-UNNAMED" myjar.jar throws

Unknown option: '--runopt=--add-opens java.base/java.lang=ALL-UNNAMED'

[quintesse]

Indeed, because .078 isn't the latest version :-)
Upgrade to 0.79 and it'll work.