Update n number of records using JPA with Optimistic locking

Question

I have a table with a column called "count" and I want to run a cron job that will trigger a statement that performs a SQL like this:

update summaryTable set count=4;

Note that there might be concurrent threads reading & changing the value for "count" when this cron job is triggered. The table has a version column to support Optimistic Locking.

What's an efficient way to update the count in JPA ?