Add Spring boot with Rest controller

build.gradle.kts

@@ -1,5 +1,8 @@
 plugins {
     kotlin("jvm") version "2.0.0"
+    kotlin("plugin.spring") version "1.9.22"
+    id("org.springframework.boot") version "3.1.0"
+    id("io.spring.dependency-management") version "1.1.0"
 }
 
 group = "org.example"
@@ -10,6 +13,8 @@ repositories {
 }
 
 dependencies {
+    implementation("org.springframework.boot:spring-boot-starter-web")
+    testImplementation("org.springframework.boot:spring-boot-starter-test")
     testImplementation(kotlin("test"))
 }
 

src/main/kotlin/Main.kt

@@ -1,5 +0,0 @@
-package org.example
-
-fun main() {
-    println("Hello World!")
-}

src/main/kotlin/org/example/Application.kt

@@ -0,0 +1,11 @@
+package org.example
+
+import org.springframework.boot.autoconfigure.SpringBootApplication
+import org.springframework.boot.runApplication
+
+@SpringBootApplication
+class Application
+
+fun main(args: Array<String>) {
+    runApplication<Application>(*args)
+}

src/main/kotlin/org/example/HelloController.kt

@@ -0,0 +1,13 @@
+package org.example
+
+import org.springframework.web.bind.annotation.GetMapping
+import org.springframework.web.bind.annotation.RestController
+
+@RestController
+class HelloController {
+
+    @GetMapping("/hello")
+    fun sayHello(): String {
+        return "Hello, World!"
+    }
+}