log4j.properties file - multiple loggers in same class

Question

I would like to have two different log4j loggers in my application, and for there to be no "overlap" between the content they write to their respect logs.

For example:

• Logger1 writes INFO events related to one set of system events
• Logger2 writes INFO events related to another set of system events
• No entry should appear in the log twice

My log4j.properties is as follows:

log4j.rootLogger=DEBUG, stdout
log4j.logger.org.apache=DEBUG, stdout
log4j.logger.xdasLogger=DEBUG, xdas

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%m%n

log4j.appender.xdas=org.apache.log4j.ConsoleAppender
log4j.appender.xdas.layout=org.apache.log4j.PatternLayout
log4j.appender.xdas.layout.ConversionPattern=%d %-5p %c - %m%n

My Java code is as follows:

public static void main(String[] args) {
    PropertyConfigurator.configure(Client.class
            .getResource("/log4j.properties"));
    xdasLogger = Logger.getLogger("xdasLogger");
    logger = Logger.getLogger(Client.class);

    logger.info("normal");
    xdasLogger.info("xdas");
}

But my console output is as follows:

normal
2012-06-28 09:52:44,580 INFO  xdasLogger - xdas
xdas

Note that "xdas" is logged by both logger and xdasLogger, which is undesirable.

Does anyone know what changes I need to put into my log4j.properties to change the console output to the following?

normal
2012-06-28 09:52:44,580 INFO  xdasLogger - xdas

Solution (taken from accepted answer):

log4j.rootLogger=DEBUG, stdout
log4j.logger.org.apache=DEBUG, stdout
log4j.logger.xdasLogger=DEBUG, xdas

log4j.additivity.org.apache=false
log4j.additivity.xdasLogger=false

log4j.appender.stdout=org.apache.log4j.ConsoleAppender
log4j.appender.stdout.layout=org.apache.log4j.PatternLayout
log4j.appender.stdout.layout.ConversionPattern=%m%n

log4j.appender.xdas=org.apache.log4j.ConsoleAppender
log4j.appender.xdas.layout=org.apache.log4j.PatternLayout
log4j.appender.xdas.layout.ConversionPattern=%d %-5p %c - %m%n

Answer 1

Try setting the additivity of the loggers to false. This will avoid the propagation to the rootLogger.

log4j.additivity.org.apache=false
log4j.additivity.xdasLogger=false