jlink / log4j2 2.21.1

[CodeDead]

Description

Without using any log4j2 plugins and after upgrading to log4j 2.21.0 or 2.21.1 I am having issues bundling log4j2-core with my jlink'd build. I think this has something to do with an incorrect dependency being set in the module-info file introduced in log4j2 2.21.0

Configuration

Version: 2.21.0, 2.21.1

Operating system: Windows 10, Windows 11, Fedora Linux 38

JDK: 17 - 21

Logs

Directly from jlink:

Error: Module org.apache.logging.log4j.core does not read a module that exports javax.annotation.processing

Reproduction

Try a jlink build. Not using any log4j2 plugins.

[ppkarwasz]

@CodeDead,

The problem seems to come from the fact that log4j-core contains an annotation processor:

provides javax.annotation.processing.Processor with org.apache.logging.log4j.core.config.plugins.processor.PluginProcessor

The processor itself depends on the java.compiler module, which is optional:

requires static java.compiler

We should probably remove static from the java.compiler module. @jvz, @vy, what do you think?

You can easily work around this problem, by adding --add-modules java.compiler to the jlink invocation.

Remark: Even if we solve this problem, jlink complains about log4j-api:

[ERROR] Error: java.lang.RuntimeException: Module org.apache.logging.log4j's descriptor indicates the set of packages is : [org.apache.logging.log4j.status, org.apache.logging.log4j.message, org.apache.logging.log4j.util, org.apache.logging.log4j.simple, org.apache.logging.log4j, org.apache.logging.log4j.internal, org.apache.logging.log4j.spi], but module contains packages: [org.apache.logging.log4j.status, org.apache.logging.log4j, org.apache.logging.log4j.util.internal, org.apache.logging.log4j.internal, org.apache.logging.log4j.spi, org.apache.logging.log4j.util, org.apache.logging.log4j.message, org.apache.logging.log4j.simple]

In this case the problem is that META-INF/versions/9 contains a new package (org.apache.logging.log4j.util.internal), which is not present in the Java 8 version.

[ppkarwasz]

I am marking this as a feature request, since with the previous versions of log4j-core JLink failed with:

[ERROR] Error: automatic module cannot be used with jlink: org.apache.logging.log4j.core from file:///home/piotr/.m2/repository/org/apache/logging/log4j/log4j-core/2.20.0/log4j-core-2.20.0.jar

[vy]

@CodeDead, could you provide us a simple (the simplest possible, please!) instruction set to reproduce your issue? Such that we can validate it indeed worked against 2.20.0 and got broken in 2.21.0.

[ppkarwasz]

I created a sample custom JRE built in:

https://github.com/apache/logging-log4j-samples/tree/main/log4j-samples-jlink

[CodeDead]

@vy @ppkarwasz

Sample using gradle and log4j2 2.20.0
https://github.com/CodeDead/sample-log4j2

It is sufficient to run the jlink task in Gradle.

The problem @ppkarwasz is seeing with log4j2 2.20.0 is not an issue with the beryx jlink plugin (but it does create a merged module-info file itself).

---

As for jlinking with log4j2 2.21.0, in addition to adding the requires java.compiler you will also need to add requires java.naming as a work-around and force-use the following packages:

    uses 'org.apache.logging.log4j.util.PropertySource'
    uses 'org.apache.logging.log4j.spi.Provider'
    uses 'org.apache.logging.log4j.message.ThreadDumpMessage.ThreadInfoFactory'