# The usual stuff. Note that A1 is configured in root not in "some.cat"
log4j.rootLogger=DEBUG, A1
log4j.appender.A1=org.apache.log4j.ConsoleAppender

log4j.appender.A1.layout=org.apache.log4j.PatternLayout
log4j.appender.A1.layout.ConversionPattern=%5p [%t] %c - %m%n

# Set the priority of "some.cat" to TRACE (defined in
# examples.customLevel.XLevel). This will actually have the side
# effect of instanciating a logger object having the name "some.cat"
# this will cause a ClassCastException if the logger object is cast
# as a MyLogger object.

log4j.logger.some.cat=TRACE#examples.customLevel.XLevel