Some configuration properties related to Elasticsearch are being parsed "on demand".

For example:

• org.hibernate.search.elasticsearch.impl.ElasticsearchHSQueryImpl.IndexSearcher.getScrollTimeout()
• org.hibernate.search.elasticsearch.impl.ElasticsearchHSQueryImpl.IndexSearcher.getScrollFetchSize()
• org.hibernate.search.elasticsearch.impl.ElasticsearchHSQueryImpl.IndexSearcher.getScrollBacktrackingWindowSize()

These should be parsed upfront both to ensure validation at boot time, and for performance reasons to reuse the already produced values.