== persist(): the INSERT Hibernate sends (one bind per JSON column)
sql> insert into product (attributes,dimensions,name,specs,tags) values (?,?,?,?,?)
sql> update product set attributes=?,dimensions=?,name=?,specs=?,tags=? where id=?

== what PostgreSQL stored (jsonb text)
attributes = {"color": "red", "price": 19.90, "ratio": 0.5, "stock": 12, "active": true, "nested": {"k": [1, 2, 3]}, "nothing": null, "bigNumber": 3000000000}
tags = ["lighting", "office"]
dimensions = {"depthMm": 180, "widthMm": 180, "heightMm": 420}
specs = {"material": "steel", "weightKg": 1.8, "certifications": ["CE", "RoHS"]}

== loaded back in a new session: Java types of the Map values
color      -> String       red
price      -> Double       19.9
ratio      -> Double       0.5
stock      -> Integer      12
active     -> Boolean      true
nested     -> LinkedHashMap {k=[1, 2, 3]}
nothing    -> null         null
bigNumber  -> Long         3000000000
dimensions -> Dimensions[widthMm=180, heightMm=420, depthMm=180]
specs      -> steel, 1.8, [CE, RoHS]

== Java null vs JSON null vs empty
null-attrs | attributes=SQL NULL | tags=SQL NULL | dimensions=SQL NULL
empty-attrs | attributes={} | tags=[] | dimensions=SQL NULL
loaded null-attrs  : attributes=null tags=null
loaded empty-attrs : attributes={} tags=[]