Update Gradle and Kotlin version, fix compilation

Author: yole

tutorials/servlet-web-applications/build.gradle

@@ -1,5 +1,5 @@
 buildscript {
-    ext.kotlin_version = '1.1.2'
+    ext.kotlin_version = '1.3.10'
     repositories {
         jcenter()
     }
@@ -19,16 +19,3 @@ dependencies {
     compile group: 'javax', name: 'javaee-api', version: '7.0'
     compile "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
 }
-
-sourceSets {
-    main {
-        kotlin {
-            srcDir "src/main/kotlin"
-        }
-    }
-    test {
-        kotlin {
-            srcDir "test/main/kotlin"
-        }
-    }
-}

tutorials/servlet-web-applications/gradle/wrapper/gradle-wrapper.properties

@@ -3,4 +3,4 @@ distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-2.8-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.10-all.zip

tutorials/servlet-web-applications/src/main/kotlin/HomeController.kt

@@ -5,7 +5,7 @@ import javax.servlet.http.HttpServlet
 import javax.servlet.http.HttpServletRequest
 import javax.servlet.http.HttpServletResponse
 
-@WebServlet(name = "Hello", value = "/hello")
+@WebServlet(name = "Hello", value = ["/hello"])
 class HomeController : HttpServlet() {
     override fun doGet(req: HttpServletRequest, res: HttpServletResponse) {
         res.writer.write("Hello, World!")