If you want to configure the logging framework used at runtime you can add the following to the run() method:

System.setProperty("net.spy.log.LoggerImpl", "net.spy.memcached.compat.log.SunLogger");

Or:

System.setProperty("net.spy.log.LoggerImpl", "net.spy.memcached.compat.log.Log4JLogger");

The default logger simply logs everything to the standard error stream.