Configuration `locale` variable is deprecated – Android

Hope this helps, I also added the getters.

@SuppressWarnings("deprecation")
public Locale getSystemLocaleLegacy(Configuration config){
    return config.locale;
}

@TargetApi(Build.VERSION_CODES.N)
public Locale getSystemLocale(Configuration config){
    return config.getLocales().get(0);
}

@SuppressWarnings("deprecation")
public void setSystemLocaleLegacy(Configuration config, Locale locale){
    config.locale = locale;
}

@TargetApi(Build.VERSION_CODES.N)
public void setSystemLocale(Configuration config, Locale locale){
    config.setLocale(locale);
}

public static void setLanguage(Context context, String languageCode){
    Locale locale = new Locale(languageCode);
    Locale.setDefault(locale);
    Configuration config = new Configuration();
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
        setSystemLocale(config, locale);
    }else{
        setSystemLocaleLegacy(config, locale);
    }
    if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1)
        context.getApplicationContext().getResources().updateConfiguration(config,
            context.getResources().getDisplayMetrics());
}

UPDATE 12/3/2016

Since context.getApplicationContext().getResources().updateConfiguration() is now deprecated, I highly recommend that you check out this solution and adopt a different approach to overwriting Android system configuration.

Better Solution: https://stackoverflow.com/a/40704077/2199894