AOT-generated JDBC repository throws ClassCastException for query methods returning Set

When Ahead-of-Time (AOT) repository generation is enabled, a derived (or possibly annotated) query method that declares Set<T> as its return type compiles successfully, but the generated *Impl__AotRepository class throws a ClassCastException at runtime, because the generated code builds a java.util.ArrayList internally and attempts to return/cast it as a Set.

This appears to be the JDBC-module equivalent of two already-confirmed issues in sibling Spring Data modules:

• Spring Data JPA: ClassCastException: ArrayList cannot be cast to Set under native-image;

• Spring Data MongoDB: AOT-generated repository fails to compile for query methods returning Set.

Steps to reproduce

1. Define a repository with a derived query method returning Set<T>:

public interface EntityRepository extends CrudRepository<Entity, Long> {
    Set<Entity> findAllBy(...);
}

2. Enable AOT repository generation (spring.aot.enabled=true, or run the compileAotJava / Spring Boot AOT build task);

3. Invoke the query method at runtime.

Generated Code

/**
 * AOT generated implementation of {@link EntityRepository#findAllBy(...)}.
 */
public Set<Entity> findAllBy(...) {
   ...
   ...

   RowMapper rowMapper = getRowMapperFactory().create(Entity.class);

   List result = (List) getJdbcOperations().query(query, parameterSource, new RowMapperResultSetExtractor<>(rowMapper));

   return (Set<Entity>) convertMany(result, Entity.class);
}

Expected behavior

The method should return a Set<T> (e.g. wrapping the raw query results in a LinkedHashSet or similar), matching the behavior of the reflective/non-AOT execution path, which handles the Set return type correctly.

Actual behavior

ClassCastException is thrown at runtime:

Caused by: java.lang.ClassCastException: class java.util.ArrayList cannot be cast to class java.util.Set (java.util.ArrayList and java.util.Set are in module java.base of loader 'bootstrap') at com.example.aot.repository.EntityRepositoryImpl__AotRepository.findAllBy(EntityRepositoryImpl__AotRepository.java:56)

Environment

• Spring Data Relational / JDBC version: 4.x.x.

Start by reproducing the failure with a JDBC repository method returning Set and the compileAotJava or Spring Boot AOT build task. Inspect the generated *Impl__AotRepository method and compare it with the reflective execution path. Done means the AOT-generated method returns a Set without ClassCastException and a regression test covers the behavior.