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The plan is to migrate all logging to use the SLF4J classes and afterwards to remove any SLF4J plugin from Wonder. That is Wonder won't be logging anything out of the box. If you use Wonder you will have to add the SLF4J plugin that you want to your project. By this you can control yourself if you want to log via log4j, commons logging, LOGBack or any other available framework.
Wonder could provide some optional logging framework that includes basic configuration and libraries for beginners to setup a simple log setup if they should not be wanting to take this step yet.
Using slf4j without log4j
In light of CVE-2021-44228, it makes sense to completely substitute log4j with something else, which can be done by using log4j-over-slf4j.