Set log level on App Engine for JRuby

config.ru

require 'appengine-rack'
AppEngine::Rack.configure_app(
    :application => 'application-id',
    :system_properties => {'java.util.logging.config.file' =>
                           'WEB-INF/classes/logging.properties'},
    :precompilation_enabled => true,
    :sessions_enabled => true,
    :version => "1")

logging.properties

# Specify the handlers to create in the root logger
# (all loggers are children of the root logger)
# The following creates two handlers 
handlers = java.util.logging.ConsoleHandler, java.util.logging.FileHandler

# Set the default logging level for the root logger
.level = ALL

# Set the default logging level for new ConsoleHandler instances
java.util.logging.ConsoleHandler.level = INFO

# Set the default logging level for new FileHandler instances
java.util.logging.FileHandler.level = ALL

# Set the default formatter for new ConsoleHandler instances
java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter

# Set the default logging level for the logger named com.mycompany
com.mycompany.level = ALL