Mark SimpleServiceManager as
import static com.google.common.base.Preconditions.checkNotNull;
import com.google.common.collect.MapMaker;
+import com.google.inject.Singleton;
import org.spongepowered.api.Sponge;
import org.spongepowered.api.event.SpongeEventFactory;
import org.spongepowered.api.event.cause.Cause;
/**
* The default implementation of {@link ServiceManager}.
*/
+@Singleton
public class SimpleServiceManager implements ServiceManager {
private final ConcurrentMap<Class<?>, ProviderRegistration<?>> providers =
