Add a parameter to select the java version for generated Quarkus projects (CLI and Maven)

[ia3andy]

Description

Continuing on #20849

The current implementation (👆) uses the shell java version to determine a compatible version (11 or 17 for now) in generated project.

We need to add this as a parameter (11 or 17, default still being automatic based on shell java version) in the CLI and Maven plugin.

Implementation ideas

See comment #21629 (comment)

[quarkus-bot]

/cc @ebullient, @maxandersen, @quarkusio/devtools

[maxandersen]

The current implementation (👆) uses the shell java version for the generated project.

where is that done ? That means if you run on on java 8,9,10,12,13,14,15, 16 or 17 what happens?

I think its a bad default to use the shell java version. It should be a fixed default (i.e. Java 11 until Java 17 is mainstream) to work reliably.

[ia3andy]

The current implementation (👆) uses the shell java version for the generated project.

where is that done ? That means if you run on on java 8,9,10,12,13,14,15, 16 or 17 what happens?

I think its a bad default to use the shell java version. It should be a fixed default (i.e. Java 11 until Java 17 is mainstream) to work reliably.

https://github.com/quarkusio/quarkus/pull/20849/files#diff-e3a379680d4a534804bfaf1f30197ae16808192379a05287be973b77585a8cc6

[abmushfiq]

i want to contribute to this issue please help me?

[ia3andy]

First question is the name?

1. java-version / javaVersion
2. java-target / javaTarget

(I do prefer 1.)

Maven Plugin:
https://github.com/quarkusio/quarkus/blob/main/devtools/maven/src/main/java/io/quarkus/maven/CreateProjectMojo.java

CLI CreateApp (need to decide with @ebullient where to add the parameter) :
https://github.com/quarkusio/quarkus/blob/main/devtools/cli/src/main/java/io/quarkus/cli/CreateApp.java

Method to set java target (if we decide to use javaVersion as name we should rename the method) already exists in the CreateProject Builder:
https://github.com/quarkusio/quarkus/blob/main/independent-projects/tools/devtools-common/src/main/java/io/quarkus/devtools/commands/CreateProject.java#L101

[maxandersen]

cli already has flags for --java, maybe have version as a optional value for it ? --java=11 ?

That does though cause a bit of mess since you can't then specify java version when using --kotlin as it currently excludes use of --java. I'm wondering if we shouldn't make target language be implicitly java so you don't need --java to set target language to java?

Then you can do quarkus create --java=11 --kotlin or quarkus create --java=17

So --java simply is used to set targeted java version?

[ebullient]

I could drop java from the exclusive language group, and use it as a java version setting flag instead... unless we should be adding a --jvm option for setting the version (even when used with kotlin or scala)