Remove explicit references to Java versions in the generator

Closes gh-543

initializr-generator/src/main/java/io/spring/initializr/generator/ProjectGenerator.java

@@ -447,10 +447,11 @@ public class ProjectGenerator {
 		model.put("servletInitializrImport", new Imports(request.getLanguage()).add(
 				getServletInitializrClass(request)).toString());
 
+		// Kotlin-specific dep
+		model.put("kotlinStdlibArtifactId", getKotlinStdlibArtifactId(request));
+
 		// Java versions
-		model.put("isJava6", isJavaVersion(request, "1.6"));
-		model.put("isJava7", isJavaVersion(request, "1.7"));
-		model.put("isJava8", isJavaVersion(request, "1.8"));
+		model.put("java8OrLater", isJava8OrLater(request));
 
 		// Append the project request to the model
 		BeanWrapperImpl bean = new BeanWrapperImpl(request);
@@ -549,6 +550,22 @@ public class ProjectGenerator {
 		}
 	}
 
+	protected String getKotlinStdlibArtifactId(ProjectRequest request) {
+		String javaVersion = request.getJavaVersion();
+		if ("1.6".equals(javaVersion)) {
+			return "kotlin-stdlib";
+		}
+		else if ("1.7".equals(javaVersion)) {
+			return "kotlin-stdlib-jre7";
+		}
+		return "kotlin-stdlib-jre8";
+	}
+
+	private static boolean isJava8OrLater(ProjectRequest request) {
+		return !request.getJavaVersion().equals("1.6")
+				&& !request.getJavaVersion().equals("1.7");
+	}
+
 	private static boolean isGradleBuild(ProjectRequest request) {
 		return "gradle".equals(request.getBuild());
 	}
@@ -574,10 +591,6 @@ public class ProjectGenerator {
 		return VERSION_2_0_0_M3.compareTo(bootVersion) < 0;
 	}
 
-	private static boolean isJavaVersion(ProjectRequest request, String version) {
-		return request.getJavaVersion().equals(version);
-	}
-
 	private byte[] doGenerateMavenPom(Map<String, Object> model) {
 		return templateRenderer.process("starter-pom.xml", model).getBytes();
 	}

initializr-generator/src/main/resources/templates/starter-build.gradle

@@ -46,13 +46,13 @@ apply plugin: 'war'
 
 group = '{{groupId}}'
 version = '{{version}}'
-sourceCompatibility = {{javaVersion}}{{#kotlin}}{{#isJava8}}
+sourceCompatibility = {{javaVersion}}{{#kotlin}}{{#java8OrLater}}
 compileKotlin {
 	kotlinOptions.jvmTarget = "1.8"
 }
 compileTestKotlin {
 	kotlinOptions.jvmTarget = "1.8"
-}{{/isJava8}}{{/kotlin}}
+}{{/java8OrLater}}{{/kotlin}}
 
 repositories {
 	mavenCentral()
@@ -83,15 +83,7 @@ dependencies {
 	compile('org.codehaus.groovy:groovy')
 	{{/groovy}}
 	{{#kotlin}}
-	{{#isJava6}}
-	compile("org.jetbrains.kotlin:kotlin-stdlib:${kotlinVersion}")
-	{{/isJava6}}
-	{{#isJava7}}
-	compile("org.jetbrains.kotlin:kotlin-stdlib-jre7{{^kotlinSupport}}:${kotlinVersion}{{/kotlinSupport}}")
-	{{/isJava7}}
-	{{#isJava8}}
-	compile("org.jetbrains.kotlin:kotlin-stdlib-jre8{{^kotlinSupport}}:${kotlinVersion}{{/kotlinSupport}}")
-	{{/isJava8}}
+	compile("org.jetbrains.kotlin:{{kotlinStdlibArtifactId}}{{^kotlinSupport}}:${kotlinVersion}{{/kotlinSupport}}")
 	compile("org.jetbrains.kotlin:kotlin-reflect{{^kotlinSupport}}:${kotlinVersion}{{/kotlinSupport}}")
 	{{/kotlin}}
 	{{#runtimeDependencies}}

initializr-generator/src/main/resources/templates/starter-pom.xml

@@ -49,15 +49,7 @@
 		{{#kotlin}}                                                     
 		<dependency>
 			<groupId>org.jetbrains.kotlin</groupId>
-			{{#isJava6}}
-			<artifactId>kotlin-stdlib</artifactId>
-			{{/isJava6}}
-			{{#isJava7}}
-			<artifactId>kotlin-stdlib-jre7</artifactId>
-			{{/isJava7}}
-			{{#isJava8}}
-			<artifactId>kotlin-stdlib-jre8</artifactId>
-			{{/isJava8}}
+			<artifactId>{{kotlinStdlibArtifactId}}</artifactId>
 			{{^kotlinSupport}}
 			<version>${kotlin.version}</version>
 			{{/kotlinSupport}}
@@ -189,9 +181,9 @@
 						<plugin>spring</plugin>
 					</compilerPlugins>
 					{{^kotlinSupport}}
-					{{#isJava8}}
+					{{#java8OrLater}}
 					<jvmTarget>1.8</jvmTarget>
-					{{/isJava8}}
+					{{/java8OrLater}}
 					{{/kotlinSupport}}
 				</configuration>
 				{{^kotlinSupport}}

initializr-generator/src/test/java/io/spring/initializr/generator/ProjectGeneratorBuildTests.java

@@ -215,6 +215,17 @@ public class ProjectGeneratorBuildTests extends AbstractProjectGeneratorTests {
 				"project/" + build + "/kotlin-springboot2-" + assertFileName));
 	}
 
+	@Test
+	public void kotlinJava9() {
+		ProjectRequest request = createProjectRequest();
+		request.setLanguage("kotlin");
+		request.setBootVersion("2.0.0.M6");
+		request.setJavaVersion("9");
+		ProjectAssert project = generateProject(request);
+		project.sourceCodeAssert(fileName).equalsTo(new ClassPathResource(
+				"project/" + build + "/kotlin-java9-" + assertFileName));
+	}
+
 	@Override
 	public ProjectRequest createProjectRequest(String... styles) {
 		ProjectRequest request = super.createProjectRequest(styles);

initializr-generator/src/test/resources/project/gradle/kotlin-java9-build.gradle.gen

@@ -0,0 +1,46 @@
+buildscript {
+	ext {
+		kotlinVersion = '1.1.1'
+		springBootVersion = '2.0.0.M6'
+	}
+	repositories {
+		mavenCentral()
+		maven { url "https://repo.spring.io/snapshot" }
+		maven { url "https://repo.spring.io/milestone" }
+	}
+	dependencies {
+		classpath("org.springframework.boot:spring-boot-gradle-plugin:${springBootVersion}")
+		classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVersion}")
+		classpath("org.jetbrains.kotlin:kotlin-allopen:${kotlinVersion}")
+	}
+}
+
+apply plugin: 'kotlin'
+apply plugin: 'kotlin-spring'
+apply plugin: 'eclipse'
+apply plugin: 'org.springframework.boot'
+apply plugin: 'io.spring.dependency-management'
+
+group = 'com.example'
+version = '0.0.1-SNAPSHOT'
+sourceCompatibility = 9
+compileKotlin {
+	kotlinOptions.jvmTarget = "1.8"
+}
+compileTestKotlin {
+	kotlinOptions.jvmTarget = "1.8"
+}
+
+repositories {
+	mavenCentral()
+	maven { url "https://repo.spring.io/snapshot" }
+	maven { url "https://repo.spring.io/milestone" }
+}
+
+
+dependencies {
+	compile('org.springframework.boot:spring-boot-starter')
+	compile("org.jetbrains.kotlin:kotlin-stdlib-jre8")
+	compile("org.jetbrains.kotlin:kotlin-reflect")
+	testCompile('org.springframework.boot:spring-boot-starter-test')
+}

initializr-generator/src/test/resources/project/maven/kotlin-java9-pom.xml.gen

@@ -0,0 +1,115 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+
+	<groupId>com.example</groupId>
+	<artifactId>demo</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<packaging>jar</packaging>
+
+	<name>demo</name>
+	<description>Demo project for Spring Boot</description>
+
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.0.0.M6</version>
+		<relativePath/> <!-- lookup parent from repository -->
+	</parent>
+
+	<properties>
+		<kotlin.compiler.incremental>true</kotlin.compiler.incremental>
+		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+		<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
+		<java.version>9</java.version>
+	</properties>
+
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.jetbrains.kotlin</groupId>
+			<artifactId>kotlin-stdlib-jre8</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.jetbrains.kotlin</groupId>
+			<artifactId>kotlin-reflect</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+	</dependencies>
+
+	<build>
+		<sourceDirectory>${project.basedir}/src/main/kotlin</sourceDirectory>
+		<testSourceDirectory>${project.basedir}/src/test/kotlin</testSourceDirectory>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+			</plugin>
+			<plugin>
+				<artifactId>kotlin-maven-plugin</artifactId>
+				<groupId>org.jetbrains.kotlin</groupId>
+				<configuration>
+					<compilerPlugins>
+						<plugin>spring</plugin>
+					</compilerPlugins>
+				</configuration>
+				<dependencies>
+					<dependency>
+						<groupId>org.jetbrains.kotlin</groupId>
+						<artifactId>kotlin-maven-allopen</artifactId>
+						<version>${kotlin.version}</version>
+					</dependency>
+				</dependencies>
+			</plugin>
+		</plugins>
+	</build>
+
+	<repositories>
+		<repository>
+			<id>spring-snapshots</id>
+			<name>Spring Snapshots</name>
+			<url>https://repo.spring.io/snapshot</url>
+			<snapshots>
+				<enabled>true</enabled>
+			</snapshots>
+		</repository>
+		<repository>
+			<id>spring-milestones</id>
+			<name>Spring Milestones</name>
+			<url>https://repo.spring.io/milestone</url>
+			<snapshots>
+				<enabled>false</enabled>
+			</snapshots>
+		</repository>
+	</repositories>
+
+	<pluginRepositories>
+		<pluginRepository>
+			<id>spring-snapshots</id>
+			<name>Spring Snapshots</name>
+			<url>https://repo.spring.io/snapshot</url>
+			<snapshots>
+				<enabled>true</enabled>
+			</snapshots>
+		</pluginRepository>
+		<pluginRepository>
+			<id>spring-milestones</id>
+			<name>Spring Milestones</name>
+			<url>https://repo.spring.io/milestone</url>
+			<snapshots>
+				<enabled>false</enabled>
+			</snapshots>
+		</pluginRepository>
+	</pluginRepositories>
+
+
+</project>