You're shooting yourself in the foot by making it private:
- it's seen as unused by PMD and the IDEs (and, transitively, all the other private methods it calls, too). So you or a collegue might mistakenly remove private methods that are actually used.
- It makes it much harder to unit-test them.
- It's unconventional, making your code look weird to experienced Spring developers.
- They're logically public, since they're called by code outside of the class and package.