FrancescoJo

// UserEntity.kt
@Entity
@Table(name = "users")
class UserEntity(
    @Id @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id")
    val id: Long = 0L,

    @Column(name = "isDeleted")
    var isDeleted: Boolean = false,

FrancescoJo

@Repository(UserReadonlyRepository.NAME)
interface UserReadonlyRepository {
  suspend fun findById(userId: UUID): User?
  
  companion object {
    const val NAME = "a.b.c.UserReadonlyRepository"
  }
}

@Repository(UserRepository.NAME)

FrancescoJo

// given:
interface SomeController {
    @RequestMapping(GET, "/someApi")
    fun someApi(): Response1
}

@RestController
class SomeControllerImpl : SomeController {
    override fun someApi1(): Response1 {
        // ...

FrancescoJo

import org.springframework.beans.factory.config.ConfigurableListableBeanFactory 
import org.springframework.beans.factory.support.BeanDefinitionRegistry 
import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor 
import org.springframework.context.annotation.ClassPathScanningCandidateComponentProvider 
import org.springframework.context.annotation.Configuration 
import org.springframework.core.type.filter.AnnotationTypeFilter 

@Configuration 
class AnnotationConfig : BeanDefinitionRegistryPostProcessor { 
    override fun postProcessBeanFactory(beanFactory: ConfigurableListableBeanFactory) { 

FrancescoJo

//usr/bin/env jshell --show-version "$0" "$@"; exit $?
public class Runner {
  public static void main(final String[] args) {
    System.out.println("Runner#main");
  }
}

System.out.println("Executing class");
Runner.main(new String[0]);

FrancescoJo

console.log("%cGood to go!", "font: 2em roboto; color: yellow; background-color: green;");

FrancescoJo

class Animal { }

class Reptile extends Animal { }
class Bird extends Animal { }

interface MobileLife {
  // Every classes derived from this interface should implement common features on it.
  void move(double displacement);

  double getDistance();

FrancescoJo

class Animal { }

class Reptile extends Animal { }
class Bird extends Animal { }

mixin MobileLife {
  // We don't need to implement _move on every classes using this mixin, since mixin can include state.
  var _distance = 0.0;
  
  void _move(double displacement) {

FrancescoJo

interface UserRepository : JpaRepository<User, Long>, UserRepositoryExtension

interface UserRepositoryExtension {
  /*
   * Here we get exception as following:
   *
   * Caused by: java.lang.IllegalArgumentException: Failed to create query for method 
   *   public abstract User UserRepositoryExtension.getByRoleCriteria(java.lang.String,java.util.Set)!
   *     At least 2 parameter(s) provided but only 1 parameter(s) present in query.
   *

FrancescoJo

interface EnumWithKey<T, K> {
    val T.key: K
}

/*
 * The reified type parameter lets you call the function without explicitly 
 * passing the Class-object.
 */
inline fun <reified T : Enum<T>, R> EnumWithKey<T, R>.byKey(key: R): T? {
    return enumValues<T>().find { it.key == key }