Justj JRE included instead of JRE 21.0.9 when building with Tycho 5

[StephFo]

Hi,
Since a few days, when I build my application instead of including Just JRE runtime 21.0.x version 25 is included instead of.
Tycho version is 5.0.0 to build my app and my .target file only contains this site to fetch JustJ.

<location followRepositoryReferences="false" includeAllPlatforms="false" includeConfigurePhase="true" includeMode="slicer" includeSource="true" type="InstallableUnit">
			<repository location="https://download.eclipse.org/justj/jres/21/updates/release/"/>
			<unit id="org.eclipse.justj.openjdk.hotspot.jre.full.stripped.feature.group" version="21.0.9.v20251105-0741"/>
</location>

During materialize-products I can see JustJ 25 is downloaded:

[materialize-products - org.lcelb.accounts.manager.app.product - macosx/cocoa/x86_64] Installing org.lcelb.accounts.manager.app.product 3.3.0.v20251107_2136.
[INFO] [materialize-products - org.lcelb.accounts.manager.app.product - macosx/cocoa/x86_64] Installing org.lcelb.accounts.manager.app.feature.feature.group 3.0.0.v20251107_2136.
[INFO] [materialize-products - org.lcelb.accounts.manager.app.product - macosx/cocoa/x86_64] Installing org.eclipse.justj.openjdk.hotspot.jre.full.stripped.feature.group 25.0.0.v20250930-1716.
[INFO] Downloading from p2: https://download.eclipse.org/justj/jres/25/updates/release/25.0.0/features/org.eclipse.justj.openjdk.hotspot.jre.full.stripped_25.0.0.v20250930-1716.jar
[INFO] Downloading from p2: https://mirror.aarnet.edu.au/pub/eclipse/justj/jres/25/updates/release/25.0.0/plugins/org.eclipse.justj.openjdk.hotspot.jre.full.stripped.macosx.x86_64_25.0.0.v20250930-1716.jar

Any idea is welcome to explain, why suddenly it includes 25 version instead of 21.0.9 as specified in .target file.
Does anyone have an idea to force Tycho to pickup 21.0.x version.

Stéphane

[StephFo]

Hi,
Finally, I've found a workaround:
Instead of defining the JustJ site in the target definition file as described above, I've replaced by defining JustJ p2 repo in root pom file like this:

<repositories>
		<repository>
			<id>justj</id>
			<layout>p2</layout>
			<url>https://download.eclipse.org/justj/jres/21/updates/release/</url>
		</repository>
</repositories>

Now JustJ JRE is fetched correctly:

[materialize-products - org.lcelb.accounts.manager.app.product - macosx/cocoa/x86_64] Installing org.lcelb.accounts.manager.app.product 3.3.0.v20251107_2200.
[INFO] [materialize-products - org.lcelb.accounts.manager.app.product - macosx/cocoa/x86_64] Installing org.lcelb.accounts.manager.app.feature.feature.group 3.0.0.v20251107_2200.
[INFO] [materialize-products - org.lcelb.accounts.manager.app.product - macosx/cocoa/x86_64] Installing org.eclipse.justj.openjdk.hotspot.jre.full.stripped.feature.group 21.0.9.v20251105-0741.
[INFO] 

Either the problem is in Tycho 5 when processing the JustJ site from target definition processing by following a link to 25 ?
Or it is an issue in JustJ site itself ?

Any though appreciated.

Stéphane

[laeubi]

It should not matter where you define it, so it is maybe some kind of other configuration that interfere here. If you can give a small self contained example it would be easier to analyze as from some (log) fragments.

[StephFo]

Hi,
Thank you for your reply and you're right something was interfering.

In this post (https://github.com/eclipse-tycho/tycho/discussions/4791#discussioncomment-14264138) we were discussing about JRE inclusion into a product.
In my context, I do prefer include stripped version as described in the post. Then in .product file I also include org.eclipse.justj.openjdk.hotspot.jre.full.stripped as root feature.

The issue I've done is : I let The Product includes JRE option checked in .product file.

If Just JRE site is declared in the .target file it leads to inconsistent JRE selection as mentioned above in the post even if you select a version in target definition.
If Just JRE site is declared in pom through a repository declaration, it selects systematically latest JRE 21.

To solve, I've just unticked The Product includes JRE and now if JustJ site is included through target definition, the correct JRE is selected and included in the build.
I did some tests with 21.0.8 or 21.0.9, Tycho build pickups the good one.

I don't know how Tycho resolves the correct JRE (which criteria) to select when The Product includes JRE is ticked.
In my product file, I have no reference to JavaSE-25 and the build is running against JavaSE-21.

Stéphane