Here is an example of using the DefaultNestedComponentRegistry class from the logback library:

import ch.qos.logback.core.spi.DefaultNestedComponentRegistry;
import ch.qos.logback.core.spi.LifeCycle;

public class NestedComponentExample {
    public static void main(String[] args) {
        DefaultNestedComponentRegistry registry = new DefaultNestedComponentRegistry();
        LifeCycle componentA = new MyComponentA();
        LifeCycle componentB = new MyComponentB();
        LifeCycle componentC = new MyComponentC();
        
        registry.add(componentA);
        registry.add(componentB);
        registry.add(componentC);

        // starting all components
        registry.start();

        // do some processing

        // stopping all components
        registry.stop();
    }

    static class MyComponentA extends LifeCycle {
        public void start() {
            // implementation to start the component
        }

        public void stop() {
            // implementation to stop the component
        }
    }

    static class MyComponentB extends LifeCycle {
        public void start() {
            // implementation to start the component
        }

        public void stop() {
            // implementation to stop the component
        }
    }

    static class MyComponentC extends LifeCycle {
        public void start() {
            // implementation to start the component
        }

        public void stop() {
            // implementation to stop the component
        }
    }
}

In this example, a DefaultNestedComponentRegistry object is instantiated, and three LifeCycle components (MyComponentA, MyComponentB, and MyComponentC) are added to it.

The start() method is called on the registry to start all of the registered components, and the stop() method is called to stop them when they are no longer needed.

It is worth noticing that this example is also an old example and it is not the recommended way of adding logback components, Instead you should use the Context object to configure the logger and its appenders/encoders.