=== Logging ===

You can configure logging by using the Java -Dlog.config=filename option.
This option uses a logging configuration file that allows you to enable and
disable specific logging messages. This is useful if you want to see
certain types of message that are not logged by default or choose where the
messages should be written. The configuration file contains details of the
handler(s) used to write the messages, parameters used to format the
messages and the severity of messages that should be logged at Java package
or class level, plus a default value. An example file is:

# The default level FINE, WARNING, INFO, SEVERE 
.level=SEVERE
#handlers: java.util.logging.ConsoleHandler 
handlers: java.util.logging.FileHandler java.util.logging.ConsoleHandler 
# package or class name with .level appended and then the level
uk.me.parabola.imgfmt.level=INFO
uk.me.parabola.mkgmap.build.level=INFO
uk.me.parabola.mkgmap.main.Main.level=INFO
uk.me.parabola.mkgmap.main.MapMaker.level=INFO
uk.me.parabola.mkgmap.general.RoadNetwork.level=INFO
uk.me.parabola.mkgmap.general.MapLine.level=INFO
uk.me.parabola.mkgmap.osmstyle.level=INFO
uk.me.parabola.mkgmap.reader.osm.level=INFO
uk.me.parabola.mkgmap.reader.osm.xml.level=INFO
uk.me.parabola.mkgmap.reader.osm.RestrictionRelation.level=FINE
uk.me.parabola.mkgmap.reader.osm.Restriction.level=FINE
# For ConsoleHandler
java.util.logging.ConsoleHandler.level=WARNING
java.util.logging.ConsoleHandler.formatter=uk.me.parabola.log.UsefulFormatter
# For FileHandler
java.util.logging.FileHandler.level=FINE
java.util.logging.FileHandler.encoding=UTF-8
java.util.logging.FileHandler.formatter=uk.me.parabola.log.UsefulFormatter
java.util.logging.FileHandler.limit=20000000
java.util.logging.FileHandler.count=4
java.util.logging.FileHandler.pattern=mkgmap.log
java.util.logging.FileHandler.append=false

The above example enables certain informational messages and sends them to a
log file, with warning and error messages being also sent to stdout.

Further information can be found at
https://docs.oracle.com/javase/8/docs/technotes/guides/logging/overview.html

