java -Dlogback.configurationFile=/path/to/config.xml chapters.configuration.MyApp1

System.setProperty("logback.configurationFile", "/path/to/config.xml");

class Main {
  static { System.setProperty("logback.configurationFile", "/path/to/config.xml");}
  private final Logger LOG = LoggerFactory.getLogger(Main.class);

  public void main (String[] args) { ... }
}

LoggerContext loggerContext = (LoggerContext) LoggerFactory.getILoggerFactory();
JoranConfigurator configurator = new JoranConfigurator();
InputStream configStream = FileUtils.openInputStream(logbackPropertiesUserFile);
configurator.setContext(loggerContext);
configurator.doConfigure(configStream); // loads logback file
configStream.close();