fix toString() method in configuration implementations (apache#3599)

[anindita-sarkarArray]

Added toString implementation to AbstractConfiguration and removed from all derived classes.

[garydgregory]

Why? This makes debugging worse as we loosing information.

[anindita-sarkarArray]

Why? This makes debugging worse as we loosing information.

hi @garydgregory , instead of AbstractConfiguration , shall I put my changes to all derived classes so that it can retain the additional info of subclasses.

[github-actions[bot]]

Job	Requested goals	Build Tool Version	Build Outcome	Build Scan®
build-macos-latest	clean install	3.9.8	:white_check_mark:
build-ubuntu-latest	clean install	3.9.8	:white_check_mark:
build-windows-latest	clean install	3.9.8	:white_check_mark:

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[garydgregory]

I am still -1 here: toString() is for debugging. If a call site needs a different view on the object, then it can call another method on that object or build that view (like a String) itself.

[ppkarwasz]

Hi @anindita-sarkarArray,

I discussed this with @garydgregory, and I agree that the toString() methods should remain unchanged to preserve a better debugging experience within IDEs.

Following the discussion in #3100, I also think it's a good idea to reduce verbosity in Log4j Core by default. With that in mind, I propose the following:

1. Downgrade the log level of the INFO messages I added in LoggerContext and AbstractConfiguration to DEBUG, with one exception:

   • Keep the INFO message at: https://github.com/apache/logging-log4j2/blob/422c385dc9450d4f620a23d84abe2d6a0aa5b9fb/log4j-core/src/main/java/org/apache/logging/log4j/core/config/AbstractConfiguration.java#L328-L334

2. Add an INFO message in LoggerContext.setConfiguration(Configuration) to notify users when a new configuration becomes active (i.e., after the updateLoggers() call). The message could be formatted like:

   <logger_context_class_name>[name=<name>] is using <configuration_class_name>[location=<location>, lastModified=<last_modified>].
   

Let me know what you think.