Convert all code to Kotlin.

build.gradle.kts

@@ -6,6 +6,10 @@ plugins {
     id("com.gradle.build-scan") version "2.0.2"
     id("org.springframework.boot") version "2.1.1.RELEASE"
     kotlin("jvm") version "1.3.11"
+    // https://kotlinlang.org/docs/reference/compiler-plugins.html#spring-support
+    id("org.jetbrains.kotlin.plugin.spring") version "1.3.11"
+    // https://kotlinlang.org/docs/reference/compiler-plugins.html#jpa-support
+    id("org.jetbrains.kotlin.plugin.jpa") version "1.3.11"
 }
 
 repositories {
@@ -38,6 +42,10 @@ sourceSets {
     }
 }
 
+tasks.test {
+    useJUnitPlatform()
+}
+
 val integrationTestImplementation by configurations.getting {
     extendsFrom(configurations.testImplementation.get())
 }
@@ -54,50 +62,53 @@ val integrationTest = task<Test>("integrationTest") {
 }
 
 dependencies {
+    // Kotlin
+    compile(kotlin("stdlib-jdk8"))
+
     // Spring Boot
-    implementation(enforcedPlatform("org.springframework.boot:spring-boot-dependencies:2.1.1.RELEASE"))
+    compile(enforcedPlatform("org.springframework.boot:spring-boot-dependencies:2.1.1.RELEASE"))
 
     // web
-    implementation("org.springframework.boot:spring-boot-starter-web")
+    compile("org.springframework.boot:spring-boot-starter-web")
 
     // database
-    implementation("org.springframework.boot:spring-boot-starter-data-jpa")
-    implementation("org.hibernate:hibernate-java8")
+    compile("org.springframework.boot:spring-boot-starter-data-jpa")
+    compile("org.hibernate:hibernate-java8")
     runtime("org.postgresql:postgresql:42.2.2")
-    implementation("org.flywaydb:flyway-core:5.0.7")
+    compile("org.flywaydb:flyway-core:5.0.7")
 
-    implementation("org.bitbucket.cowwoc:requirements-core:4.0.4-RC")
+    compile("org.bitbucket.cowwoc:requirements-core:4.0.4-RC")
 
     // Jackson
-    implementation("com.fasterxml.jackson.core:jackson-databind:2.9.7")
-    implementation("com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.9.7")
+    compile("com.fasterxml.jackson.core:jackson-databind:2.9.7")
+    compile("com.fasterxml.jackson.dataformat:jackson-dataformat-yaml:2.9.7")
+    compile("com.fasterxml.jackson.module:jackson-module-kotlin:2.9.7")
 
     // because of Java 9+
     // https://stackoverflow.com/questions/43574426/how-to-resolve-java-lang-noclassdeffounderror-javax-xml-bind-jaxbexception-in-j#43574427
     // https://blog.sourced-bvba.be/article/2017/12/17/java9-spring/
-    implementation("javax.xml.bind:jaxb-api:2.3.0")
-    implementation("com.sun.xml.bind:jaxb-impl:2.3.0")
-    implementation("org.glassfish.jaxb:jaxb-runtime:2.3.0")
-    implementation("javax.activation:activation:1.1.1")
+    compile("javax.xml.bind:jaxb-api:2.3.0")
+    compile("com.sun.xml.bind:jaxb-impl:2.3.0")
+    compile("org.glassfish.jaxb:jaxb-runtime:2.3.0")
+    compile("javax.activation:activation:1.1.1")
 
     // dev tools
-    implementation("org.springframework.boot:spring-boot-devtools")
+    compile("org.springframework.boot:spring-boot-devtools")
 
-    testImplementation("org.springframework.boot:spring-boot-starter-test")
-    testImplementation("org.springframework.boot:spring-boot-test-autoconfigure")
+    testCompile("org.springframework.boot:spring-boot-starter-test")
+    testCompile("org.springframework.boot:spring-boot-test-autoconfigure")
 
     // JUnit 5
-    testImplementation("org.junit.jupiter:junit-jupiter-api:5.3.2")
+    testCompile("org.junit.jupiter:junit-jupiter-api:5.3.2")
     testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.3.2")
 
     // Support running JUnit 4 tests using JUnit 5
     testCompileOnly("junit:junit:4.12")
     testRuntimeOnly("org.junit.vintage:junit-vintage-engine:5.3.2")
 
     // H2 in-memory database
-    testImplementation("com.h2database:h2:1.4.197")
+    testCompile("com.h2database:h2:1.4.197")
 
 //    integrationTestCompile("org.seleniumhq.selenium:selenium-java:3.13.0")
 //    integrationTestCompile("org.seleniumhq.selenium:selenium-remote-driver:3.13.0")
-    compile(kotlin("stdlib-jdk8"))
 }