This is a follow-up to my previous, duplicate question Why is NetBeans saying "incompatible thrown types IOException in method reference"? [duplicate]. Why does NetBeans tell me "unreported exception IOException; must be caught or declared to be thrown" when I catch the IOException?
Screenshot of error

Full method code
/**
 * Either extracts or returns the pre-extracted language file for the given locale
 * 
 * @param locale the locale 
 * @return
 * @throws IOException 
 */
public static InputStream getLanguageFile(Locale locale) throws IOException
{
    File extracted = SaveConstants.inventSaveFileFor(Main.GAME_NAME, locale.toLanguageTag() + ".lang");
    if (!extracted.exists())
    {
        InputStream in = Resources.getLanguageStream(locale);
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        extracted.getParentFile().mkdirs();
        try
        {
            extracted.createNewFile();
            Writer writer = new FileWriter(extracted);
            reader
                .lines()
                .forEach((str) -> writer.write(str));
        }
        catch (IOException ex)
        {
            Logger.getLogger(Lang.class.getName()).log(Level.SEVERE, "Cannot extract language file for " + locale + ". Loading directly to map", ex);
            return in;
        }
    }
    else
        return new FileInputStream(extracted);
}
Note: I know it won't compile because of a missing return, but I want to get this down before I move on to the return
