code: protected static boolean initializeLogging() {
          try {
  
              // initial logging config, used before anything else
              {
                  final URL url = Main.class.getResource("log4j-initial.xml");
                  assert url != null;
                  DOMConfigurator.configure(url);
              }
  
              if (ClassLoaderUtils.IS_WEB_START) {
                  final URL url = Main.class.getResource("log4j-jnlp.xml");
                  assert url != null;
                  println("Using JNLP log configuration: " + url);
                  DOMConfigurator.configure(url);
                  return true;
              }
  
              final File dataCleanerHome = DataCleanerHome.getAsFile();
              if (initializeLoggingFromDirectory(dataCleanerHome)) {
                  return true;
              }
  
              if (initializeLoggingFromDirectory(new File("."))) {
                  return true;
              }
  
              // fall back to default log4j.xml file in classpath
              final URL url = Main.class.getResource("log4j-default.xml");
              assert url != null;
              println("Using default log configuration: " + url);
              DOMConfigurator.configure(url);
              return false;
  
          } catch (final NoClassDefFoundError e) {
              // can happen if log4j is not on the classpath
              println("Failed to initialize logging, class not found: " + e.getMessage());
              return false;
          }
      }
docs: Initializes logging, specifically by looking for log4j.xml or
  log4j.properties file in DataCleaner's home directory.
  
  @return true if a logging configuration file was found, or false
  otherwise