Ok, but we are only using elastic search indexes. And on one application we are only pointing it to one elaticsearch cluster that is locally on that box only. So as far as I know, we are not mixing these two things. As I’ve not provided any local file directory for lucene under the hibernate config. And hibernate config only points to a single elastic search cluster.

That's not what your stacktraces tells me. You probably forgot to set the index manager type to "elasticsearch" for at least one of your indexes:

# Do this to make it the default for all indexes
hibernate.search.default.indexmanager = elasticsearch
# Do this to use Elasticsearch for one index in particular
hibernate.search.myIndex1.indexmanager = elasticsearch

Also please look below in the snapshot of my local tomcat server. You can see hibernate search threads. These threads keep on running intermittently and never stops.

These are the threads that perform indexing.

The threads will not stop as long as your application is running. That's on purpose.

The threads run intermittently when you index something. That's on purpose.

Was your only problem that "Hibernate Search creates threads"?