SignalHandler to gracefully shutdown a Play 2.5 app

SignalHandler.java

import akka.actor.ActorSystem;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import play.api.inject.DefaultApplicationLifecycle;
import scala.concurrent.duration.Duration;
import scala.concurrent.duration.FiniteDuration;
import sun.misc.Signal;

import javax.inject.Inject;
import javax.inject.Singleton;
import java.util.concurrent.TimeUnit;

@Singleton
public class SignalHandler {
  private static final Logger LOG = LoggerFactory.getLogger(SignalHandler.class);

  // Docker will kill the container in 10s by default. Give some time to log things before exiting.
  private static final FiniteDuration STOP_DELAY = Duration.create(9500, TimeUnit.MILLISECONDS);

  @Inject
  SignalHandler(ActorSystem actorSystem, DefaultApplicationLifecycle lifecycle) {
    LOG.info("Add signal handler hooks to the application");

    Signal.handle(new Signal("TERM"), signal -> {
      LOG.info("Shutdown hook: signal {} ({})", signal.getName(), signal.getNumber());
      onApplicationStop(actorSystem, lifecycle);
    });
  }

  private void onApplicationStop(ActorSystem actorSystem, DefaultApplicationLifecycle lifecycle) {
    LOG.info("Termination required. Swallowing signal to allow current requests to finish");
    actorSystem.scheduler().scheduleOnce(STOP_DELAY, lifecycle::stop, actorSystem.dispatcher());
  }
}