Constructor is accessed twice when persisting Java 16 records

[hajdamak]

When new Java record is persisted using repository's save method, it's constructor is called twice with the same parameters.
One should be enough to set id and/or version.

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]

This is a general issue in Spring Data JDBC where the version number is being set twice:

• AggregateChangeExecutor -> execute -> executeInsertRoot -> RelationalEntityVersionUtils.setVersionNumberOnEntity
• AggregateChangeExecutor -> executionContext.populateRootVersionIfNecessary(root)

[hajdamak]

@mp911de Additional note, during this operation properties are accessed twice each, except Id which is accessed 3 times.

[mp911de]

Additional property access is required to create new instances of an object.