class DefaultExtensionFinder implements ExtensionFinder, PluginStateListener {

    protected PluginManager pluginManager;
    protected List<ExtensionFinder> finders = new ArrayList<>();

    public DefaultExtensionFinder(PluginManager pluginManager) {
        this.pluginManager = pluginManager;

        add(new LegacyExtensionFinder(pluginManager));
//        add(new ServiceProviderExtensionFinder(pluginManager));
    }

    @Override
    public <T> List<ExtensionWrapper<T>> find(Class<T> type) {
        List<ExtensionWrapper<T>> extensions = new ArrayList<>();
        for (ExtensionFinder finder : finders) {
            extensions.addAll(finder.find(type));
        }

        return extensions;
    }

    @Override
    public <T> List<ExtensionWrapper<T>> find(Class<T> type, String pluginId) {
        List<ExtensionWrapper<T>> extensions = new ArrayList<>();
        for (ExtensionFinder finder : finders) {
            extensions.addAll(finder.find(type, pluginId));
        }

        return extensions;
    }

    @Override
    public List<ExtensionWrapper> find(String pluginId) {
        List<ExtensionWrapper> extensions = new ArrayList<>();
        for (ExtensionFinder finder : finders) {
            extensions.addAll(finder.find(pluginId));
        }

        return extensions;
    }

    @Override
    public Set<String> findClassNames(String pluginId) {<FILL_FUNCTION_BODY>}

    @Override
    public void pluginStateChanged(PluginStateEvent event) {
        for (ExtensionFinder finder : finders) {
            if (finder instanceof PluginStateListener) {
                ((PluginStateListener) finder).pluginStateChanged(event);
            }
        }
    }

    public DefaultExtensionFinder addServiceProviderExtensionFinder() {
        return add(new ServiceProviderExtensionFinder(pluginManager));
    }

    public DefaultExtensionFinder add(ExtensionFinder finder) {
        finders.add(finder);

        return this;
    }

}

        Set<String> classNames = new HashSet<>();
        for (ExtensionFinder finder : finders) {
            classNames.addAll(finder.findClassNames(pluginId));
        }

        return classNames;
    
<no_super_class>