project setting "Store information about method parameters" cannot be changed for individual projects in a multi-root workspace

[aaron-stambler-delta]

Environment:

• VS Code Version: 1.107.1
• Extension Version: 0.31.0
• JDK Type & Version: RedHat 17.0.18
• OS Type & Version: Windows 26100.8246

Step to Reproduce:

• Load a multi-root workspace with multiple Java projects.
• Open Project Settings by going to the JAVA PROJECTS pane, clicking the ellipsis/More Actions..., and choosing Configure Java Runtime.
• Change the Project to the second project.
• Choose the Compiler section.
• Toggle "Store information about method parameters" to on.
• Click Apply Settings.

Expected Behavior:
The selected project should have been built with the -parameters flag.

Actual Behavior:
The -parameters flag was not used.

Related Issues:
I can no longer toggle this switch for an individual project. The toggle remains set or unset for all projects.
This is a new problem since installing this version of the extension. It worked in the previous version.

[github-actions]

Hi @aaron-stambler-delta, I'm an AI Support assistant here to help with your issue. While the team reviews your request, I wanted to provide some possible tips and documentation that might help you in the meantime.

Possible Workaround

While the per-project UI toggle for "Store information about method parameters" appears to be broken in a multi-root workspace, there is a known file-based workaround. You can apply the setting directly to each project by creating (or editing) a .settings/org.eclipse.jdt.core.prefs file in each project's root folder with the following content:

eclipse.preferences.version=1
org.eclipse.jdt.core.compiler.codegen.methodParameters=generate

The property org.eclipse.jdt.core.compiler.codegen.methodParameters=generate is the Eclipse JDT equivalent of the -parameters javac flag. Placing this file in each project root allows the setting to be applied per-project independently, bypassing the UI bug.

Note: There is a known issue where project-level .settings/org.eclipse.jdt.core.prefs files can be overridden by workspace storage settings. If the workaround doesn't take effect, check this issue for additional context.

Related References

• How to use javac -parameters option — explains the .settings/org.eclipse.jdt.core.prefs approach for enabling method parameter storage: redhat-developer/vscode-java#1042
• Store method parameters in compiled classes — earlier discussion on enabling this compiler flag in VS Code Java: redhat-developer/vscode-java#391

Other references with low confidence

• When org.eclipse.jdt.core.prefs exists both in project root and workspace storage — the project root one may not always win; relevant context for the per-project override behavior — eclipse-jdtls/eclipse.jdt.ls#1516
• Add setting to disable for a folder in multi-root workspace — related discussion on per-folder settings in multi-root workspaces — microsoft/vscode-maven#500

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The team will respond to your issue shortly. I hope these suggestions are helpful in the meantime. If this comment helped you, please give it a 👍. If the suggestion was not helpful or incorrect, please give it a 👎. Your feedback helps us improve!

[chagong]

@aaron-stambler-delta, thanks for reporting, we will investigate it.