Below is the property from our hibernate config.

<property name="hibernate.search.default.indexmanager">elasticsearch</property>

We have this set correctly.

These are the threads that perform indexing.

But on startup we are not indexing anything.

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

Why is so?

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

We are not indexing anything on startup. Then why are they even started. And why they keep on running, when I’m not indexing anything.

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

No, issue is these threads are throwing my application in out of memory condition. Also If I switch elastic search off in my app, then the application runs fine.