Activator.java

package com.github.cap5lut.service.test;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;

public class Activator implements BundleActivator {
    private volatile Logger logger;

    @Override
    public void start(BundleContext context) throws Exception {
        System.out.println("started");
        logger = LogManager.getLogger();
        logger.fatal("started");
    }

    @Override
    public void stop(BundleContext context) throws Exception {
        logger.fatal("stopped");
        logger = null;
        System.out.println("stopped");
    }
}