Fix dependency management.

demo-launcher/build.gradle.kts

@@ -1,7 +1,7 @@
 plugins {
     kotlin("jvm")
-    id("org.springframework.boot")
-    id("io.spring.dependency-management")
+    id("org.springframework.boot") version "3.4.3"
+    id("io.spring.dependency-management") version "1.1.7"
     id("java")
 }
 
@@ -11,5 +11,5 @@ dependencies {
 }
 
 springBoot {
-    mainClass = "com.example.demo.launcher.ApplicationLauncher"
+    mainClass = "com.example.demo.launcher.ApplicationLauncherKt"
 }

demo-launcher/src/main/kotlin/com/example/demo/launcher/ApplicationLauncher.kt

@@ -4,7 +4,7 @@ import org.springframework.boot.autoconfigure.SpringBootApplication
 import org.springframework.boot.runApplication
 
 @SpringBootApplication
-class DemoApplication
+open class DemoApplication
 
 fun main(args: Array<String>) {
     runApplication<DemoApplication>(*args)