// number 1
    /**
     * Check for language accept
     *
     * @param unacceptedLanguagesList list with unaccepted languages
     * @param language language for checking
     * @return is language accepted
     */
    private boolean isLanguageAccepted(List<String> unacceptedLanguagesList, String language)
    {
        if ( unacceptedLanguagesList == null || StringUtils.isBlank(language) ) {
            return false;
        }

        for ( String locale : unacceptedLanguagesList ) {
            if ( language.equalsIgnoreCase(locale) ) {
                return false;
            }
        }

        return true;
    }

// number 2
    /**
     * Check for language accept
     *
     * @param unacceptedLanguagesList list with unaccepted languages
     * @param language language for checking
     * @return is language accepted
     */
    private boolean isLanguageAccepted(List<String> unacceptedLanguagesList, String language)
    {
        boolean result = false;
        if ( unacceptedLanguagesList != null && StringUtils.isNotBlank(language) ) {
            result = true;

            for ( String locale : unacceptedLanguagesList ) {
                if ( language.equalsIgnoreCase(locale) ) {
                    result = false;
                    break;
                }
            }
        }
        return result;
    }

//number 3
    private static boolean isLanguageAccepted(List<String> unacceptedLanguagesList, String language) {
        boolean result = false;
        if (unacceptedLanguagesList != null && StringUtils.isNotBlank(language)) {
            ListIterator<String> listIterator = unacceptedLanguagesList.listIterator();
            result = true;
            while (listIterator.hasNext() && result) {
                if (language.equalsIgnoreCase(listIterator.next())) {
                    result = false;
                }
            }
        }
        return result;
    }


// project for check
import org.apache.commons.lang3.StringUtils;

import java.util.*;

/**
 * Created by pglukhov on 21.07.2017.
 */
public class SplitExample {
    private static final List<String> languageList = new ArrayList<>();

    static {
        languageList.add("fr");
        languageList.add("en");
        languageList.add("ru");
        languageList.add("de");
    }

    private static List<String> extractLanguages(String languages) {
        if (StringUtils.isBlank(languages)) {
            return Collections.<String>emptyList();
        }

        final String[] splittedStrings = languages.split(",");
        final List<String> languagesList = new ArrayList<>();
        for (String item : splittedStrings) {
            languagesList.add(item.trim());
        }

        return languagesList;
    }

    private static boolean isLanguageAccepted(List<String> unacceptedLanguagesList, String language) {
        boolean result = false;
        if (unacceptedLanguagesList != null && StringUtils.isNotBlank(language)) {
            ListIterator<String> listIterator = unacceptedLanguagesList.listIterator();
            result = true;
            while (listIterator.hasNext() && result) {
                if (language.equalsIgnoreCase(listIterator.next())) {
                    result = false;
                }
            }
        }
        return result;
    }

    public static void main(String[] args) {
        String langList1 = "fr";
        List<String> exceptedLanguageList = extractLanguages(langList1);
        List<String> filteredList = new ArrayList<String>();

        for (String item : languageList) {
            if (isLanguageAccepted(exceptedLanguageList, item)) {
                filteredList.add(item);
            }
        }

        System.out.println("Filtered List");
        for (String item : filteredList) {
            System.out.println(item);
        }

    }

}