Raise the minimum supported version of Gradle to 2.9

Closes gh-6884

spring-boot-dependencies/pom.xml

@@ -76,7 +76,7 @@
 		<elasticsearch.version>2.4.0</elasticsearch.version>
 		<gemfire.version>8.2.0</gemfire.version>
 		<glassfish-el.version>3.0.0</glassfish-el.version>
-		<gradle.version>1.12</gradle.version>
+		<gradle.version>2.9</gradle.version>
 		<groovy.version>2.4.7</groovy.version>
 		<gson.version>2.7</gson.version>
 		<h2.version>1.4.193</h2.version>

spring-boot-docs/src/main/asciidoc/getting-started.adoc

@@ -39,8 +39,8 @@ diverge from the defaults.
 By default, Spring Boot {spring-boot-version} requires http://www.java.com[Java 7] and
 Spring Framework {spring-version} or above. You can use Spring Boot with Java 6 with some
 additional configuration. See <<howto.adoc#howto-use-java-6>> for more details. Explicit
-build support is provided for Maven (3.2+) and Gradle (1.12 or 2.x). Support for Gradle
-2.8 and earlier is deprecated. Gradle 3 is not supported.
+build support is provided for Maven (3.2+) and Gradle 2 (2.9 or later). Gradle 3 is not
+supported.
 
 TIP: Although you can use Spring Boot with Java 6 or 7, we generally recommend Java 8 if
 at all possible.
@@ -205,9 +205,9 @@ scope.
 
 [[getting-started-gradle-installation]]
 ==== Gradle installation
-Spring Boot is compatible with Gradle 1.12 or 2.x but support for 2.8 and earlier is
-deprecated. Gradle 2.14.1 is recommended. Gradle 3 is not supported. If you don't already
-have Gradle installed you can follow the instructions at http://www.gradle.org/.
+Spring Boot is compatible with Gradle 2 (2.9 or later). Gradle 2.14.1 is recommended and
+Gradle 3 is not supported. If you don't already have Gradle installed you can follow the
+instructions at http://www.gradle.org/.
 
 Spring Boot dependencies can be declared using the `org.springframework.boot` `group`.
 Typically your project will declare dependencies to one or more

spring-boot-integration-tests/spring-boot-gradle-tests/src/test/java/org/springframework/boot/gradle/BootRunResourceTests.java

@@ -50,7 +50,7 @@ public class BootRunResourceTests {
 	public void resourcesDirectlyFromSource() {
 		project.newBuild().forTasks("clean", "bootRun")
 				.withArguments("-PbootVersion=" + BOOT_VERSION, "-PaddResources=true")
-				.run();
+				.setStandardOutput(System.out).run();
 
 		assertThat(this.output.toString()).contains("src/main/resources/test.txt");
 	}
@@ -59,7 +59,7 @@ public class BootRunResourceTests {
 	public void resourcesFromBuildOutput() {
 		project.newBuild().forTasks("clean", "bootRun")
 				.withArguments("-PbootVersion=" + BOOT_VERSION, "-PaddResources=false")
-				.run();
+				.setStandardOutput(System.out).run();
 		assertThat(this.output.toString()).contains("build/resources/main/test.txt");
 	}
 

spring-boot-integration-tests/spring-boot-gradle-tests/src/test/java/org/springframework/boot/gradle/ProjectCreator.java

@@ -34,7 +34,7 @@ public class ProjectCreator {
 	private String gradleVersion;
 
 	public ProjectCreator() {
-		this("1.12");
+		this("2.9");
 	}
 
 	public ProjectCreator(String gradleVersion) {

spring-boot-integration-tests/spring-boot-gradle-tests/src/test/resources/spring-loaded-jvm-args/build.gradle

@@ -9,6 +9,7 @@ buildscript {
 	}
 }
 
+apply plugin: 'application'
 apply plugin: 'java'
 apply plugin: 'org.springframework.boot'
 

spring-boot-parent/pom.xml

@@ -192,6 +192,16 @@
 				<artifactId>aether-util</artifactId>
 				<version>${aether.version}</version>
 			</dependency>
+			<dependency>
+				<groupId>org.gradle</groupId>
+				<artifactId>gradle-base-services</artifactId>
+				<version>${gradle.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>org.gradle</groupId>
+				<artifactId>gradle-base-services-groovy</artifactId>
+				<version>${gradle.version}</version>
+			</dependency>
 			<dependency>
 				<groupId>org.gradle</groupId>
 				<artifactId>gradle-core</artifactId>
@@ -199,12 +209,17 @@
 			</dependency>
 			<dependency>
 				<groupId>org.gradle</groupId>
-				<artifactId>gradle-base-services</artifactId>
+				<artifactId>gradle-language-java</artifactId>
 				<version>${gradle.version}</version>
 			</dependency>
 			<dependency>
 				<groupId>org.gradle</groupId>
-				<artifactId>gradle-base-services-groovy</artifactId>
+				<artifactId>gradle-language-jvm</artifactId>
+				<version>${gradle.version}</version>
+			</dependency>
+			<dependency>
+				<groupId>org.gradle</groupId>
+				<artifactId>gradle-platform-jvm</artifactId>
 				<version>${gradle.version}</version>
 			</dependency>
 			<dependency>

spring-boot-tools/spring-boot-gradle-plugin/pom.xml

@@ -33,6 +33,11 @@
 			<artifactId>groovy</artifactId>
 			<scope>provided</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.gradle</groupId>
+			<artifactId>gradle-base-services</artifactId>
+			<scope>provided</scope>
+		</dependency>
 		<dependency>
 			<groupId>org.gradle</groupId>
 			<artifactId>gradle-core</artifactId>
@@ -40,7 +45,17 @@
 		</dependency>
 		<dependency>
 			<groupId>org.gradle</groupId>
-			<artifactId>gradle-base-services</artifactId>
+			<artifactId>gradle-language-java</artifactId>
+			<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.gradle</groupId>
+			<artifactId>gradle-language-jvm</artifactId>
+			<scope>provided</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.gradle</groupId>
+			<artifactId>gradle-platform-jvm</artifactId>
 			<scope>provided</scope>
 		</dependency>
 		<dependency>

spring-boot-tools/spring-boot-gradle-plugin/src/main/java/org/springframework/boot/gradle/plugin/SpringBootPlugin.java

@@ -22,9 +22,6 @@ import org.gradle.api.Project;
 import org.gradle.api.Task;
 import org.gradle.api.plugins.JavaPlugin;
 import org.gradle.api.tasks.compile.JavaCompile;
-import org.gradle.util.GradleVersion;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
 
 import org.springframework.boot.gradle.SpringBootPluginExtension;
 import org.springframework.boot.gradle.agent.AgentPluginFeatures;
@@ -41,15 +38,8 @@ import org.springframework.boot.gradle.run.RunPluginFeatures;
  */
 public class SpringBootPlugin implements Plugin<Project> {
 
-	private static final Logger logger = LoggerFactory.getLogger(SpringBootPlugin.class);
-
 	@Override
 	public void apply(Project project) {
-		if (GradleVersion.current().compareTo(GradleVersion.version("2.9")) < 0) {
-			logger.warn("Spring Boot plugin's support for Gradle "
-					+ GradleVersion.current().getVersion()
-					+ " is deprecated. Please upgrade to Gradle 2.9 or later.");
-		}
 		project.getExtensions().create("springBoot", SpringBootPluginExtension.class,
 				project);
 		project.getPlugins().apply(JavaPlugin.class);
@@ -67,7 +57,6 @@ public class SpringBootPlugin implements Plugin<Project> {
 			compile.doFirst(new Action<Task>() {
 
 				@Override
-				@SuppressWarnings("deprecation")
 				public void execute(Task t) {
 					if (compile.getOptions().getEncoding() == null) {
 						compile.getOptions().setEncoding("UTF-8");