private static void releaseParser(SAXParser parser) {
        try {
            parser.reset();
        } catch (UnsupportedOperationException e) {
            //ignore
        }
        try {
            READ_WRITE_LOCK.readLock().lock();
            //if there are extra parsers (e.g. after a reset of the pool to a smaller size),
            // this parser will not be added and will then be gc'd
            SAX_PARSERS.offer(parser);
        } finally {
            READ_WRITE_LOCK.readLock().unlock();
        }
    }
Return parser to the pool for reuse

@param parser parser to return
tika-core/src/main/java/org/apache/tika/mime/MimeTypesReader.java