First, please use code tags when posting source code, it makes the source much easier to read. I edited your post for you this time.
As far as turning off the logging, a few ways:
a) Delete the log4j.xml file. If it is not there, logging will not be initialized. Though Log4J does complain about not finding a config file.
b) Create an appender that uses org.apache.log4j.varia.NullAppender. Then change the <root> and the <logger> entries to all reference the null appender. (A variation of this theme is to change all of the currently-defined appenders to used NullAppender.)
c) Change the levels or threshold levels of either the appenders or loggers to OFF.