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Java Hibernate Basics Persisting Data with Hibernate Updating and Deleting Entities

Posted by Ricardo Sala
Ricardo Sala
16,212 Points

Why aren't the IDs generated by Hybernate consecutive?

Pretty self explaining! :)

I am seeing that the IDs that Hybernate generates are "1, 33, 65,..."

What are those "32 missing IDs"?

2 Answers

Boban Talevski
Boban Talevski
24,793 Points
Boban Talevski
Boban Talevski
24,793 Points

As was noted in some other post regarding a previous video in this course, this can be fixed by simply closing your sessionFactory object at the end of the main method in Application.java.

I think the logic behind it was that it "grabs" the next 32 ids when opened, and unless properly closed, it doesn't "return" those unused ids, and they are lost forever. Which is the reason, why there's a gap of 32 on each subsequent application run.

So just add this right before the closing tag of the main method and it should be fixed:

sessionFactory.close();
angel juarez
angel juarez
15,886 Points
angel juarez
angel juarez
15,886 Points

thanks, I had the same issue and now it's fixed!

Ken Alger
STAFF
Ken Alger
Treehouse Teacher
Ken Alger
Ken Alger
Treehouse Teacher

I'd have a look at the documentation for ID generation in Hibernate. My guess would be that the default generator is trying to ensure uniqueness there.