@Override
    public void checkInitialization(InitializableProblemHandler problemHandler)
            throws TikaConfigException {

        if (langs.size() > 0 && !StringUtils.isBlank(defaultConfig.getLanguage())) {
            if (!langs.contains(defaultConfig.getLanguage())) {
                throw new TikaConfigException("It doesn't look like tesseract has lang data for " +
                        defaultConfig.getLanguage() + ". " + "I see only: " + langs);
            }
        }
    }
Starts a thread that reads the contents of the standard output or error
stream of the given process to not block the process. The stream is closed
once fully processed.
tika-parsers/tika-parsers-standard/tika-parsers-standard-modules/tika-parser-ocr-module/src/main/java/org/apache/tika/parser/ocr/TesseractOCRParser.java