Log4j with Tomcat .. (3 questions)

[Mufaddal Khumri]

Hi,
Am new to log4j. Am using Tomcat 5 and my webapp-myNiceWebApp is in 
Tomcat/webapps/myNiceWebApp

I have a class that I have the following code in:
                Logger logger = Logger.getLogger(Helper.class);
                SimpleLayout layout = new SimpleLayout();
                
                FileAppender appender = null;
                try
                {
                        appender = new FileAppender(layout,"output1.txt",false);
                }
                catch(Exception e)
                {
                        e.printStackTrace();
                }
                
                logger.addAppender(appender);
                logger.setLevel((Level)Level.DEBUG);
                
                logger.debug("some message");
Que 1. Where does the file output1.txt get created?
Que 2. How does log4j know where to create it and can it be controlled?
Que 3. I am going to use a configuration file either use the 
DOMConfigurator or PropertyConfigurator to load the log4j properties. 
Where do i place this file log4j configuration file?

Thanks,