Places and their PlaceCategories
#3 Normalization

What will you do if a place belongs to more than one category?  For example, I might categorize Boston as New England as well as The Northeast.  But you only have one place category ID per place.  

If the category is always a region, you might call the table Regions instead.  That's more specific than category or even place category.  

I would expect something called place categories to know to what place it belonged.  But in this case, one place category has many places.  This is part of why I don't like the name.  It feels wrong to me.  

#2 Object vs. ID

Hibernate is an Object-relational Mapping tool (ORM).  It always includes related tables as objects, but it doesn't necessarily bother loading them unless needed.  I.e. it has a lazy loading option.  It's application specific which way you do it.  If you normally need it, perhaps load it aggressively.  If you normally don't need it, perhaps you only load it lazily.  

Note that place categories are rather light weight.  It would be easy enough to load all of them and assign them as you load places.  That's a good pattern if you have to load all the categories in order to make your drop down.