what is difference implement interface at cglib proxy? - spring-boot

Question

I made 2 proxy object using ProxyFactory in Spring.
One proxy object used interface and one proxy object not used interface.
but not working jdk dynamic proxy. all proxy object used cglib.
The proxy object that implement interface call real method.
The proxy object that not implement interface has unexpected result.
What's the difference between two cglib proxy object?
The only difference between the two is the interface.
// Not implement interface
open class Person: AbstractPerson() {
}
abstract class AbstractPerson(var age: Int? = null,
var name: String? = null) {
fun init() {
this.age = 31
this.name = "LichKing"
}
fun introduce(): String = "age: $age name: $name"
}
// Implement interface
open class PersonImpl: AbstractPersonImpl() {
}
abstract class AbstractPersonImpl(var age: Int? = null,
var name: String? = null): PersonInterface {
fun init() {
this.age = 31
this.name = "LichKing"
}
override fun introduce(): String = "age: $age name: $name"
}
interface PersonInterface {
fun introduce(): String
}
// Test
class PersonTest {
#Test
fun implementInterface() {
val p = PersonImpl()
p.init()
val proxyFactory: ProxyFactory = ProxyFactory()
proxyFactory.setTarget(p)
val proxy = proxyFactory.proxy as PersonImpl
println(proxy.javaClass)
println(proxy.introduce()) // "age: 31 name: LichKing"
}
#Test
fun notImplementInterface() {
val p = Person()
p.init()
val proxyFactory: ProxyFactory = ProxyFactory()
proxyFactory.setTarget(p)
val proxy = proxyFactory.proxy as Person
println(proxy.javaClass)
println(proxy.introduce()) // "age: null name: null"
}
}

Answer 1

kotlin method's default option is final.
The cause is introduce method not be extend.
default option is open when using interface so it's could be extended.
gradle plugin kotlin-spring is only for spring annotations.
It does not work for abstract class.