Polish "Add toolchains support for Spring Boot Maven Plugin"

See gh-18732

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/it/run-toolchains/pom.xml

@@ -25,7 +25,10 @@
 				</executions>
 				<configuration>
 					<toolchains>
-						<jdk/>
+						<jdk>
+							<version>42</version>
+							<vendor>test</vendor>
+						</jdk>
 					</toolchains>
 				</configuration>
 			</plugin>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/it/run-toolchains/toolchains.xml

@@ -1,6 +1,10 @@
 <toolchains>
 	<toolchain>
 		<type>jdk</type>
+		<provides>
+			<version>42</version>
+			<vendor>test</vendor>
+		</provides>
 		<configuration>
 			<jdkHome>jdkHome</jdkHome>
 		</configuration>

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/it/run-toolchains/verify.groovy

@@ -1,3 +1,2 @@
 def file = new File(basedir, "build.log")
 return file.text.contains("The Maven Toolchains is awesome!")
-

spring-boot-project/spring-boot-tools/spring-boot-maven-plugin/src/main/java/org/springframework/boot/maven/AbstractRunMojo.java

@@ -69,6 +69,20 @@ public abstract class AbstractRunMojo extends AbstractDependencyFilterMojo {
 	@Parameter(defaultValue = "${project}", readonly = true, required = true)
 	private MavenProject project;
 
+	/**
+	 * The current Maven session. This is used for toolchain manager API calls.
+	 * @since 2.3.0
+	 */
+	@Parameter(defaultValue = "${session}", readonly = true)
+	private MavenSession session;
+
+	/**
+	 * The toolchain manager to use to locate a custom JDK.
+	 * @since 2.3.0
+	 */
+	@Component
+	private ToolchainManager toolchainManager;
+
 	/**
 	 * Add maven resources to the classpath directly, this allows live in-place editing of
 	 * resources. Duplicate resources are removed from {@code target/classes} to prevent
@@ -209,20 +223,6 @@ public abstract class AbstractRunMojo extends AbstractDependencyFilterMojo {
 	@Parameter(property = "spring-boot.run.skip", defaultValue = "false")
 	private boolean skip;
 
-	/**
-	 * The Maven Session Object.
-	 * @since 2.2.1
-	 */
-	@Parameter(defaultValue = "${session}", readonly = true)
-	private MavenSession session;
-
-	/**
-	 * The toolchain manager to use.
-	 * @since 2.2.1
-	 */
-	@Component
-	private ToolchainManager toolchainManager;
-
 	@Override
 	public void execute() throws MojoExecutionException, MojoFailureException {
 		if (this.skip) {