Db4j is an async transactional database engine that uses java as the query language. It doesn't eliminate the O/R impedance mismatch entirely (it's not a graph or object database), but it does simplify it greatly since everything is java
I love the idea and it's been fun for me to make demos with, but I've gotten almost zero feedback on the API, and what I have gotten is "can you add a SQL frontend". And yet neither ORM nor SQL are loved
So the question (and I'm not suggesting that Db4j is the answer) is: "what's the API that would be most natural ?"
https://github.com/db4j/db4j
I love the idea and it's been fun for me to make demos with, but I've gotten almost zero feedback on the API, and what I have gotten is "can you add a SQL frontend". And yet neither ORM nor SQL are loved
So the question (and I'm not suggesting that Db4j is the answer) is: "what's the API that would be most natural ?"