[LOG4J2-2664] log4j-1.2 compatibility layer seems to rely on log4j-core . It shouldn't

• Type: Bug
• Status: Closed
• Priority: Blocker
• Resolution: Duplicate
• Affects Version/s: 2.12.0
• Component/s: Log4j 1.2 bridge
• Assignee: Unassigned
• Reporter: Alexander Picoli
• Created: 24/Jul/19 15:07
• Updated: 03/Feb/21 19:59
• Resolved: 24/Jul/19 20:04

Description

I've just got a surprise that was a showstopper to me: It seems that log4j 1.2 compatibility layer demands log4j core for working well:

In our project, we are trying to use another spi that wraps around log4j 2 , so that some specific features can be enforced.

However, when I try to use log4j 1.2 compatibility layer, it fails:

 

Exception in thread "main" java.lang.ClassCastException: com.ibm.is.poclog4j.commonconfig.MandatoryAppendersLoggerContext incompatible with org.apache.logging.log4j.core.LoggerContext
    at org.apache.log4j.Logger$PrivateManager.getContext(Logger.java:59)
    at org.apache.log4j.Logger.getRootLogger(Logger.java:45)
    at com.ibm.is.poclog4j.sample.SampleLogUser.main(SampleLogUser.java:9)

 

The issue is there: org.apache.logging.log4j.core.LoggerContext : you shouldn't count with a core-based context, or else you violate the API contract, forcing people to use a specific implementation for log4j (in this case, the default core one).

My SPI uses the spi-provided interface for LoggingContext:
import org.apache.logging.log4j.spi.LoggerContext;

public class MandatoryAppendersLoggerContext implements LoggerContext {

 

Issue Links

• duplicates: LOG4J2-2556 log4j-1.2-api works only with core