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

import java.util.logging.LogManager;

import ch.qos.logback.classic.jul.JULHelper;

public class LogbackExample {
    public static void main(String[] args) {
        LogManager logManager = LogManager.getLogManager();
        java.util.logging.Logger julLogger = logManager.getLogger("");
        ch.qos.logback.classic.Logger logbackLogger =  JULHelper.asLogbackLogger(julLogger);

        logbackLogger.debug("This is a debug message");
        logbackLogger.info("This is an informational message");
        logbackLogger.error("This is an error message", new Exception("This is an exception"));
    }
}

This example uses the JULHelper class to convert a java.util.logging.Logger to a ch.qos.logback.classic.Logger and logs messages using the logback API. JULHelper is a helper class for logback-classic to bridge with java.util.logging.

It allows to use logback-classic as underlying implementation for java.util.logging API.

Please note that this example assumes that you have a logback.xml configuration file in your classpath to configure the logback loggers.

This example is only giving a sample of how JULHelper class can be used to work with logback and java.util.logging API together.