Here is an example of using the JoranConfigurator class from the logback-classic library in Java:

import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.joran.JoranConfigurator;
import ch.qos.logback.core.joran.spi.JoranException;
import ch.qos.logback.core.util.StatusPrinter;

public class LogbackExample {
    public static void main(String[] args) {
        LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();
        try {
            JoranConfigurator configurator = new JoranConfigurator();
            configurator.setContext(context);
            context.reset();
            configurator.doConfigure("logback.xml");
        } catch (JoranException je) {
            StatusPrinter.printInCaseOfErrorsOrWarnings(context);
        }
        
        Logger logger = (Logger) LoggerFactory.getLogger(LogbackExample.class);
        logger.debug("This is a debug message");
        logger.info("This is an informational message");
        logger.error("This is an error message", new Exception("This is an exception"));
    }
}

This example uses the JoranConfigurator class to configure the logger context using an XML configuration file logback.xml . The JoranConfigurator class is used to programmatically configure logback using an XML configuration file.

The setContext(context) call tells the configurator which logger context to configure, in this case it's the current logger context obtained by LoggerFactory.getILoggerFactory()

The context.reset() call resets the logger context and discards any previously configured loggers, appenders, and layouts.

The doConfigure("logback.xml") call tells the configurator to read and parse the logback.xml configuration file from the classpath

The StatusPrinter.printInCaseOfErrorsOrWarnings(context) call prints logback internal status in case of configuration errors or warnings

Please keep in mind that the logback.xml should be placed in classpath to be loaded by JoranConfigurator

This example is using basic configuration, but you can use this class in more complex scenarios by using different options and attributes.