The logback.classic.model.LogbackClassicDefaultNestedComponentRules is a class that holds the default nested component rules for logback.classic . It is part of the logback library, and it can be used to configure the logback components in a more organized way.

Here's an example of how you might use the LogbackClassicDefaultNestedComponentRules class in a Java application:

import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.model.LoggerModel;
import ch.qos.logback.classic.model.LogbackClassicDefaultNestedComponentRules;
import ch.qos.logback.core.joran.action.ActionConst;
import ch.qos.logback.core.joran.spi.JoranException;
import ch.qos.logback.core.joran.spi.RuleStore;

public class MyApplication {
  public static void main(String[] args) {
    LoggerContext loggerContext = new LoggerContext();
    RuleStore rs = new RuleStore(loggerContext);
    LogbackClassicDefaultNestedComponentRules nestedRules = new LogbackClassicDefaultNestedComponentRules(loggerContext);
    // Adding nested rules for different tags
    nestedRules.addDefaultNestedComponentRegistryRules(rs);
    // adding logger rules
    LoggerModel.addNestedComponentRegistryRules(rs);
    try {
        // do parsing here
    } catch (JoranException e) {
        e.printStackTrace();
    }
  }
}

In this example, a LoggerContext and RuleStore are created. Then we are adding the default nested component rules for the different tags like appender,encoder etc. via addDefaultNestedComponentRegistryRules(rs) method and also added the nested component rules for logger via addNestedComponentRegistryRules(rs) method.

It is important to notice that addDefaultNestedComponentRegistryRules(rs) and addNestedComponentRegistryRules(rs) both are adding the rules for different elements of configuration file, so, you can use the specific one based on your requirement.

After adding the nested rules, you can parse your configuration file and then use the install method of your ConfigurationModel or JoranConfigurator class to install the configuration to your logger context

It is worth noting that this is just a sample, you need to have a logback.xml or logback-test.xml file in your classpath or configure it manually.