log4j logging twice

Question

I am using log4j to log error and other system information. but come of the info logged twice at INFO level.

public static void main(final String... args) throws         


        

Answer 1

A potential alternative to adjusting the additivity property is to examine your loggers from most specific to most generic. In the following example, we would expect to see double logging in the Console for any log events occurring in foo.bar.LoggingExampleClass. It would be safe to remove the extra Console appender from the foo.bar.LoggingExampleClass Logger as it is already covered by the Root logger.

There are tradeoffs to both the additivity adjustment approach and the appender adjustment approach. Turning off additivity might inadvertently stop a desirable generic level logger's appender from being used. In the above example, setting the additivity="false" property on the foo.bar.LoggingExampleClass Logger would mean the logging event would not be appended to the MainLogFile referenced in the Root logger.

On the other hand, relying on parent appenders might be problematic if the parent appenders are changed without examining the effects on more granular loggers. For example, suppose there is a requirement that foo.bar.LoggingExampleClass logging events should be written to the Console. They currently are in the example configuration above due to additivity, even if the foo.bar.LoggingExampleClass Logger's Console appender is removed. However, if the Console appender was also removed from the Root logger without any additional adjustments, the requirement would no longer be met.