Here is an example of how you can use the ContextInitializer class from the logback.classic package:

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;
import org.slf4j.LoggerFactory;

public class MyClass {
  public static void main(String[] args) {
    // Get the logger context
    LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();

    // Load the configuration from a file
    try {
      JoranConfigurator configurator = new JoranConfigurator();
      configurator.setContext(context);
      context.reset();
      configurator.doConfigure("path/to/config.xml");
    } catch (JoranException je) {
      // StatusPrinter will handle this
    }

    // Print logback's internal status
    StatusPrinter.printInCaseOfErrorsOrWarnings(context);
  }
}

The ContextInitializer class is used to initialize the logger context using a configuration file. In this example, we use the JoranConfigurator class to load the configuration from an XML file. The doConfigure method reads the configuration file and sets up the logger context according to the specified settings.

The StatusPrinter class is then used to print logback's internal status, which can be helpful for debugging purposes.