Case i want to recreate:

1. Application startup and put one table from postgres DB to cache
2. All querys to this table must be executed and use second level cache instead of DB connection.

build.gradle:

dependencies {
    implementation 'org.springframework.boot:spring-boot-starter-data-jpa'
    implementation 'org.hibernate.orm:hibernate-jcache:6.1.6.Final'
    implementation 'org.springframework.boot:spring-boot-starter-web'
    runtimeOnly 'org.postgresql:postgresql'
    testImplementation 'org.springframework.boot:spring-boot-starter-test'
    implementation 'org.ehcache:ehcache:3.10.8'
}

application.properties:

spring.jpa.show-sql=true
spring.jpa.properties.javax.persistence.sharedCache.mode=ENABLE_SELECTIVE
spring.jpa.properties.hibernate.format_sql=true
spring.jpa.properties.hibernate.generate_statistics=true
spring.jpa.properties.hibernate.cache.use_second_level_cache=true
spring.jpa.properties.hibernate.cache.use_query_cache=true
spring.jpa.properties.hibernate.cache.region.factory_class= 
org.hibernate.cache.jcache.JCacheRegionFactory
spring.jpa.hibernate.ddl-auto=none

Cache initialization:

@Configuration
public class CacheConfig {

    private final RegionsRepo repo;

    public CacheConfig(RegionsRepo repo) {
        this.repo = repo;
    }

    @PostConstruct
    public void initCache() {
        repo.findAll().forEach(region -> {});
    }
}

And JpaRepository:

public interface RegionsRepo extends JpaRepository<Regions, Long> {
    
    Optional<Regions> findRegionsByExternalid(Integer id);

    @Override
    Optional<Regions> findById(Long aLong);

    @Override
    @QueryHints(@QueryHint(name = org.hibernate.annotations.QueryHints.CACHEABLE, value = "true"))
    List<Regions> findAll();
}

After starup app puts table into second level hibernate cache. Log:

 346333 nanoseconds spent acquiring 1 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    73250 nanoseconds spent preparing 1 JDBC statements;
    1098084 nanoseconds spent executing 1 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    5962251 nanoseconds spent performing 3 L2C puts;
    0 nanoseconds spent performing 0 L2C hits;
    368667 nanoseconds spent performing 1 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
    68458 nanoseconds spent executing 1 partial-flushes (flushing a total of 0 entities and 0 collections)

when i call repository method

findById

which is Overrided from JpaRepository, i see that there is no execution of JDBC statement, just pure L2C hits which is what i needed.
Log:

    1277291 nanoseconds spent acquiring 1 JDBC connections;
    0 nanoseconds spent releasing 0 JDBC connections;
    0 nanoseconds spent preparing 0 JDBC statements;
    0 nanoseconds spent executing 0 JDBC statements;
    0 nanoseconds spent executing 0 JDBC batches;
    0 nanoseconds spent performing 0 L2C puts;
    418709 nanoseconds spent performing 1 L2C hits;
    0 nanoseconds spent performing 0 L2C misses;
    0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
    0 nanoseconds spent executing 0 partial-flushes (flushing a total of 0 entities and 0 collections)

BUT when i use custom, not overrided method

findRegionsByExternalid

L2C is ignored. Log:

742083 nanoseconds spent acquiring 1 JDBC connections;
0 nanoseconds spent releasing 0 JDBC connections;
849083 nanoseconds spent preparing 1 JDBC statements;
2029042 nanoseconds spent executing 1 JDBC statements;
0 nanoseconds spent executing 0 JDBC batches;
670583 nanoseconds spent performing 1 L2C puts;
0 nanoseconds spent performing 0 L2C hits;
0 nanoseconds spent performing 0 L2C misses;
0 nanoseconds spent executing 0 flushes (flushing a total of 0 entities and 0 collections);
0 nanoseconds spent executing 0 partial-flushes (flushing a total of 0 entities and 0 collections)

Could you please tell what is wrong with hibernate cache configuration in this case?