.filter(p -> !request.getPluginGroups().contains(p.getGroupId()))
                .collect(Collectors.groupingBy(
                        Plugin::getGroupId,
                        LinkedHashMap::new,
                        Collectors.mapping(Plugin::getArtifactId, Collectors.toSet())));
        request.getPluginGroups().forEach(g -> candidates.put(g, null));

        if (settings.isUsePluginRegistry()) {
            addViolation(problems, Severity.WARNING, "usePluginRegistry", null, "is deprecated and has no effect.");
        }

        List<String> pluginGroups = settings.getPluginGroups();

        if (pluginGroups != null) {
            for (int i = 0; i < pluginGroups.size(); i++) {
                String pluginGroup = pluginGroups.get(i).trim();

                if (pluginGroup.isEmpty()) {

            return;
        }
        request.setOffline(settings.isOffline());
        request.setInteractiveMode(settings.isInteractiveMode());
        request.setPluginGroups(settings.getPluginGroups());
        request.setLocalRepositoryPath(settings.getLocalRepository());
        for (Server server : settings.getServers()) {
            request.addServer(new org.apache.maven.settings.Server(server));
        }