Fix generation of Javadoc on Java 9

This commit fixes Javadoc generation when building with Java 9. It
upgrades the Javadoc plugin to a version that is Java 9 compatible
(3.0.0-M1) and reworks DevTools to remove usage of @PostConstruct.
The latter change is necessary as @PostConstruct is not visible by
default when building with Java 9 and, therefore its usage causes
Javadoc generation to fail.

Closes gh-10029

Author: wilkinsona

spring-boot-dependencies/pom.xml

@@ -217,7 +217,7 @@
 		<maven-invoker-plugin.version>3.0.0</maven-invoker-plugin.version>
 		<maven-help-plugin.version>2.2</maven-help-plugin.version>
 		<maven-jar-plugin.version>3.0.2</maven-jar-plugin.version>
-		<maven-javadoc-plugin.version>2.10.4</maven-javadoc-plugin.version>
+		<maven-javadoc-plugin.version>3.0.0-M1</maven-javadoc-plugin.version>
 		<maven-resources-plugin.version>3.0.1</maven-resources-plugin.version>
 		<maven-shade-plugin.version>2.4.3</maven-shade-plugin.version>
 		<maven-site-plugin.version>3.5.1</maven-site-plugin.version>

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/autoconfigure/HateoasObjenesisCacheDisabler.java

@@ -18,11 +18,10 @@
 
 import java.lang.reflect.Field;
 
-import javax.annotation.PostConstruct;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.beans.factory.InitializingBean;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ReflectionUtils;
 
@@ -35,22 +34,26 @@
  * @author Andy Wilkinson
  * @since 1.3.0
  */
-class HateoasObjenesisCacheDisabler {
+class HateoasObjenesisCacheDisabler implements InitializingBean {
 
 	private static final Log logger = LogFactory
 			.getLog(HateoasObjenesisCacheDisabler.class);
 
 	private static boolean cacheDisabled;
 
-	@PostConstruct
-	void disableCaching() {
+	@Override
+	public void afterPropertiesSet() {
+		disableCaching();
+	}
+
+	private void disableCaching() {
 		if (!cacheDisabled) {
 			cacheDisabled = true;
 			doDisableCaching();
 		}
 	}
 
-	void doDisableCaching() {
+	private void doDisableCaching() {
 		try {
 			Class<?> type = ClassUtils.forName(
 					"org.springframework.hateoas.core.DummyInvocationUtils",

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/autoconfigure/OptionalLiveReloadServer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2015 the original author or authors.
+ * Copyright 2012-2017 the original author or authors.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -16,11 +16,10 @@
 
 package org.springframework.boot.devtools.autoconfigure;
 
-import javax.annotation.PostConstruct;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.beans.factory.InitializingBean;
 import org.springframework.boot.devtools.livereload.LiveReloadServer;
 
 /**
@@ -30,7 +29,7 @@
  * @author Phillip Webb
  * @since 1.3.0
  */
-public class OptionalLiveReloadServer {
+public class OptionalLiveReloadServer implements InitializingBean {
 
 	private static final Log logger = LogFactory.getLog(OptionalLiveReloadServer.class);
 
@@ -44,12 +43,12 @@ public OptionalLiveReloadServer(LiveReloadServer server) {
 		this.server = server;
 	}
 
-	/**
-	 * {@link PostConstruct} method to start the server if possible.
-	 * @throws Exception in case of errors
-	 */
-	@PostConstruct
-	public void startServer() throws Exception {
+	@Override
+	public void afterPropertiesSet() throws Exception {
+		startServer();
+	}
+
+	void startServer() throws Exception {
 		if (this.server != null) {
 			try {
 				if (!this.server.isStarted()) {

spring-boot-devtools/src/main/java/org/springframework/boot/devtools/remote/client/RemoteClientConfiguration.java

@@ -24,11 +24,10 @@
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 
-import javax.annotation.PostConstruct;
-
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.beans.factory.InitializingBean;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
@@ -70,7 +69,7 @@
  */
 @Configuration
 @EnableConfigurationProperties(DevToolsProperties.class)
-public class RemoteClientConfiguration {
+public class RemoteClientConfiguration implements InitializingBean {
 
 	private static final Log logger = LogFactory.getLog(RemoteClientConfiguration.class);
 
@@ -111,7 +110,10 @@ private ClientHttpRequestInterceptor getSecurityInterceptor() {
 		return new HttpHeaderInterceptor(secretHeaderName, secret);
 	}
 
-	@PostConstruct
+	public void afterPropertiesSet() {
+		logWarnings();
+	}
+
 	private void logWarnings() {
 		RemoteDevToolsProperties remoteProperties = this.properties.getRemote();
 		if (!remoteProperties.getRestart().isEnabled()) {

spring-boot-devtools/src/test/java/org/springframework/boot/devtools/autoconfigure/HateoasObjenesisCacheDisablerTests.java

@@ -55,7 +55,7 @@ public void cacheIsEnabledByDefault() {
 
 	@Test
 	public void cacheIsDisabled() {
-		new HateoasObjenesisCacheDisabler().doDisableCaching();
+		new HateoasObjenesisCacheDisabler().afterPropertiesSet();
 		assertThat(this.objenesis.getInstantiatorOf(TestObject.class))
 				.isNotSameAs(this.objenesis.getInstantiatorOf(TestObject.class));
 	}