How to know the version of Eclipse formatter ?

[Maze-fr]

Context :
I use the formatter-maven-plugin for global formating (old code, global formatting rule change, CI, etc.).
It can use an Eclipse formatter XML file.
The point is to use the same file with formatter-maven-plugin and for java.format.settings.url.

Problem :
I would like to be sure that the rules I use are the same and correctly interpreted by both formatter-maven-plugin and for java.format.settings.url.
formatter-maven-plugin provides an Eclipse Version Compatibility table.
How can I identify the version used by "Language Support for Java" plugin ?

[rgrunber]

Looking at https://github.com/eclipse-jdt/eclipse.jdt.ui/blob/master/org.eclipse.jdt.core.manipulation/common/org/eclipse/jdt/internal/ui/preferences/formatter/ProfileVersionerCore.java , the current version is 23 and apparently hasn't bee updated since 2023.

The formatter XML file has a version field. If you provide a particular version in your formatter xml file, the settings from that particular version should be respected. I'm not sure how formatter-maven-plugin would work though. It may just use the latest formatter version available for that Eclipse release.

[Maze-fr]

I didn't find a way to know which version of JDT is shipped with vscode-java, and so to find the information about "version 23".
I actually use version 23 on my profile, so everything is fine. For now...
But what will happen if there is a "version 24" next year ?
Also, not knowing clearly which version of the formatter is used inside vscode-java may result in différences with the result of formatter-maven-plugin (ex : bug correction), and it actually happened before.

Maybe, like it's done with Lombok, it would be nice to use the version of the formatter dependency specified by Maven if present ?

[rgrunber]

The easiest way is probably to download the particular vsix of vscode-java you're interested in from https://github.com/redhat-developer/vscode-java/releases (or even from OpenVSX) and run something like :

$ curl -L -O https://open-vsx.org/api/redhat/java/1.45.0/file/redhat.java-1.45.0.vsix
...
$ unzip -Z1 redhat.java-1.45.0.vsix | grep jdt.core_
extension/server/plugins/org.eclipse.jdt.core_3.43.0.v20250820-1501.jar

Alternatively, if you have you're vscode-java extension already installed :

$ ls -1 ~/.vscode/extensions/redhat.java-1.46.2025092508-linux-x64/server/plugins/ | grep jdt.core_
org.eclipse.jdt.core_3.44.0.v20250923-0213.jar

If a newer version of the formatter comes out, then it should continue to be supported if you create a formatter file that specifies a previous version. The only issue would be if the formatter plugin or vscode-java release a newer version of the JDT Core formatter, before the other has adopted it. We can't support swapping out the version of JDT Core at-will as that could break the entire JDT-LS runtime.

[Maze-fr]

Il like that last command, I added it (adapted it) to my project. Thank you.

Indeed, there is little probabilities that we come to an issue as the version is specified on the profile.