Which version of org.apache.logging.log4j.log4j-slf4j2-impl supports org.slf4j.slf4j-api version 2.0.0 or more

[bbhansali1]

We are mandated to upgrade org.slf4j.slf4j-api to version greater than 2.0.0 but when we upgrade it OSGI framework complaints that current version (2.17.1) of org.apache.logging.log4j.log4j-slf4j2-impl supports SLF4J version greater than equal to 1.7.0 and less than equal to 2.0.0

We checked all the versions of org.apache.logging.log4j.log4j-slf4j2-impl till Beta 3 but none of them supports SLF4J version greater than 2.0.0

Can you please help if their is a plan to release a supported version or any workaround?

[ppkarwasz]

@bbhansali1,

You are probably talking about the log4j-slf4j-impl artifact (bundle symbolic name org.apache.logging.log4j.slf4j-impl before version 2.21.0 and org.apache.logging.log4j.slf4j.impl since then). That artifact will only support SLF4J 1.x.

SLF4J 2.x does not bring any major (i.e. breaking) changes to the public API, but it has breaking changes for providers, therefore we had to introduce a new artifact log4j-slf4j2-impl to support it. That is the artifact that you want to use.

BTW: I see that from a user perspective having two variants of the same SLF4J-to-Log4j API bridge is confusing. Would it help if we deprecate log4j-slf4j-impl and remove it from the distribution in the next two minor releases? Or do you still have some OSGi bundles that require SLF4J 1.x?

[bbhansali1]

Thanks @ppkarwasz for quick response.

yes this was confusing as i downloaded all the versions of log4j-slf4j-impl and none of them supported org.apache.logging.log4j.slf4j-impl version 2 or greater.

Either deprecating it or adding a note to point to log4j-slf4j2-impl will help.

Thanks,
Bharat

[ppkarwasz]

@bbhansali1,

Could you point us to the misleading documentation? We fixed the /log4j/2.x/log4j-slf4j-impl documentation page a long time ago, but there might be other references on our website that we missed.

[bbhansali1]

@ppkarwasz,

what i meant is if you can add documentation on https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-slf4j-impl which points to https://mvnrepository.com/artifact/org.apache.logging.log4j/log4j-slf4j2-impl it will help users.