Spurious warning about incompatible .class files version in required binaries

[oliviercailloux]

When I add logback 1.5.6 as a dependency in my POM, vscode tells me: “Incompatible .class files version in required binaries. Project 'simple' is targeting a 17 runtime, but is compiled against '(…)/.m2/repository/ch/qos/logback/logback-core/1.5.6/logback-core-1.5.6.jar' (from the container 'Maven Dependencies') which requires a 21 runtime”.

I believe that the warning is incorrect: extracting the content of .m2/repository/ch/qos/logback/logback-core/1.5.6/logback-core-1.5.6.jar and running javap -verbose on a few classes reveal a major version equal to 55.

The JAR is a multi-release one, including some classes specific to Java 21. I suspect that this confuses vscode.

Environment

• Operating System: linux
• JDK version: 17
• Visual Studio Code version: 1.91.0
• Java extension version: v0.27.0

Steps To Reproduce

Add logback 1.5.6 as a dependency in your POM.

Here is a sample project.

Logs (partial and redacted): messages, server.

Current Result

Warning

Expected Result

No warning

Additional Informations

• mvn compile does not complain.
• Might be related to Multi-Release JARs (MRJARs) pick the wrong class on higher Java versions #3319.
• I posted an issue to logback before realizing that the problem seems to come from vscode.

[oliviercailloux]

Has anyone got a chance of looking at this? Is anything more required as a description or reproducer?

[oliviercailloux]

Just realized that this happens only when the compiler settings modify the severity related to option id org.eclipse.jdt.core.incompatibleJDKLevel