private static PoolSAXParser acquireSAXParser() throws TikaException {
        PoolSAXParser parser = null;

        //this locks around the pool so that there's
        //no race condition with it being resized
        SAX_POOL_LOCK
                .readLock()
                .lock();
        try {
            parser = SAX_PARSERS.poll();
        } finally {
            SAX_POOL_LOCK
                    .readLock()
                    .unlock();
        }
        if (parser == null) {
            LOG.warn("Contention waiting for a SAXParser. " +
                    "Consider increasing the XMLReaderUtils.POOL_SIZE");
        }
        return parser;
    }
Acquire a SAXParser from the pool.  Make sure to
{@link #releaseParser(PoolSAXParser)} in
a <code>finally</code> block every time you call this.

@return a SAXParser or null if a parser is not available
@throws TikaException
tika-core/src/main/java/org/apache/tika/utils/XMLReaderUtils.java