Field access methods are not called when persisting Java 16 records

When new Java record is persisted using repository’s save method field access methods of the record are not called to read state of the passed record.

Minimal reproducible example: hajdamak/spring-data-jdbc-record-access Requires Maven and JDK17. Call mvn spring-boot:run . Relevant output:

Saving record ...
Constructor is accessed: (null, 0, test)
Constructor is accessed: (5f5b5ea0-3c8c-4ea3-88d1-b02142d2b9b3, 1, test)
Constructor is accessed: (5f5b5ea0-3c8c-4ea3-88d1-b02142d2b9b3, 1, test)

[mp911de]

There are efforts to optimize these accesses even more by generating Java code ahead of time with Spring Native/Spring AOT. These efforts could help to avoid runtime class generation in the first place but performance-wise it would lead to the same profile and it would not change the amount of classes loaded at runtime.

[hajdamak]

I suppose I wanted to have cake and eat it too. 😉 Have standard calls and at the same time avoid manual Converter implementation. But I guess if fields are accessed using generated bytecode then all performance benefits are already in. And Java is not expressive enough to have standard calls without manual Converter implementation and without additional bytcode magic.