Deprecate LiveReload support for removal

Closes gh-48971

documentation/spring-boot-docs/src/docs/antora/modules/reference/pages/using/devtools.adoc

@@ -108,10 +108,8 @@ The way in which you cause the classpath to be updated depends on the tool that
 NOTE: If you are restarting with Maven or Gradle using the build plugin you must leave the `forking` set to `enabled`.
 If you disable forking, the isolated application classloader used by devtools will not be created and restarts will not operate properly.
 
-TIP: Automatic restart works very well when used with LiveReload.
-See the xref:using/devtools.adoc#using.devtools.livereload[] section for details.
-If you use JRebel, automatic restarts are disabled in favor of dynamic class reloading.
-Other devtools features (such as LiveReload and property overrides) can still be used.
+TIP: If you use JRebel, automatic restarts are disabled in favor of dynamic class reloading.
+Other devtools features (such as property overrides) can still be used.
 
 NOTE: DevTools relies on the application context's shutdown hook to close it during a restart.
 It does not work correctly if you have disabled the shutdown hook (`SpringApplication.setRegisterShutdownHook(false)`).
@@ -287,11 +285,13 @@ If you find such a problem, you need to request a fix with the original authors.
 [[using.devtools.livereload]]
 == LiveReload
 
+WARNING: Given its decrease in popularity and support, the LiveReload feature is deprecated as of Spring Boot 4.1.0 with no replacement.
+
 The `spring-boot-devtools` module includes an embedded LiveReload server that can be used to trigger a browser refresh when a resource is changed.
 LiveReload browser extensions are freely available for Chrome, Firefox and Safari.
 You can find these extensions by searching 'LiveReload' in the marketplace or store of your chosen browser.
 
-If you want to start the LiveReload server when your application runs, you can set the configprop:spring.devtools.livereload.enabled[] property to `true`.
+If you want to start the LiveReload server when your application runs, you can set the `spring.devtools.livereload.enabled` property to `true`.
 
 NOTE: You can only run one LiveReload server at a time.
 Before starting your application, ensure that no other LiveReload servers are running.

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

@@ -24,6 +24,7 @@ import java.util.List;
 import org.jspecify.annotations.Nullable;
 
 import org.springframework.boot.context.properties.ConfigurationProperties;
+import org.springframework.boot.context.properties.DeprecatedConfigurationProperty;
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 import org.springframework.util.StringUtils;
 
@@ -200,6 +201,7 @@ public class DevToolsProperties {
 		 */
 		private int port = 35729;
 
+		@DeprecatedConfigurationProperty(reason = "Deprecated with no replacement", since = "4.1.0")
 		public boolean isEnabled() {
 			return this.enabled;
 		}
@@ -208,6 +210,7 @@ public class DevToolsProperties {
 			this.enabled = enabled;
 		}
 
+		@DeprecatedConfigurationProperty(reason = "Deprecated with no replacement", since = "4.1.0")
 		public int getPort() {
 			return this.port;
 		}

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

@@ -37,7 +37,6 @@ import org.springframework.boot.devtools.classpath.PatternClassPathRestartStrate
 import org.springframework.boot.devtools.filewatch.FileSystemWatcher;
 import org.springframework.boot.devtools.filewatch.FileSystemWatcherFactory;
 import org.springframework.boot.devtools.filewatch.SnapshotStateRepository;
-import org.springframework.boot.devtools.livereload.LiveReloadServer;
 import org.springframework.boot.devtools.restart.ConditionalOnInitializedRestarter;
 import org.springframework.boot.devtools.restart.RestartScope;
 import org.springframework.boot.devtools.restart.Restarter;
@@ -71,18 +70,20 @@ public final class LocalDevToolsAutoConfiguration {
 	 */
 	@Configuration(proxyBeanMethods = false)
 	@ConditionalOnBooleanProperty(name = "spring.devtools.livereload.enabled")
+	@SuppressWarnings("removal")
 	static class LiveReloadConfiguration {
 
 		@Bean
 		@RestartScope
 		@ConditionalOnMissingBean
-		LiveReloadServer liveReloadServer(DevToolsProperties properties) {
-			return new LiveReloadServer(properties.getLivereload().getPort(),
-					Restarter.getInstance().getThreadFactory());
+		org.springframework.boot.devtools.livereload.LiveReloadServer liveReloadServer(DevToolsProperties properties) {
+			return new org.springframework.boot.devtools.livereload.LiveReloadServer(
+					properties.getLivereload().getPort(), Restarter.getInstance().getThreadFactory());
 		}
 
 		@Bean
-		OptionalLiveReloadServer optionalLiveReloadServer(LiveReloadServer liveReloadServer) {
+		OptionalLiveReloadServer optionalLiveReloadServer(
+				org.springframework.boot.devtools.livereload.LiveReloadServer liveReloadServer) {
 			return new OptionalLiveReloadServer(liveReloadServer);
 		}
 
@@ -160,6 +161,7 @@ public final class LocalDevToolsAutoConfiguration {
 
 	}
 
+	@SuppressWarnings("removal")
 	static class LiveReloadServerEventListener implements GenericApplicationListener {
 
 		private final OptionalLiveReloadServer liveReloadServer;

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

@@ -30,7 +30,10 @@ import org.springframework.core.log.LogMessage;
  *
  * @author Phillip Webb
  * @since 1.3.0
+ * @deprecated since 4.1.0 for removal in 4.3.0 with no replacement.
  */
+@Deprecated(since = "4.1.0", forRemoval = true)
+@SuppressWarnings("removal")
 public class OptionalLiveReloadServer implements InitializingBean {
 
 	private static final Log logger = LogFactory.getLog(OptionalLiveReloadServer.class);

module/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/livereload/Connection.java

@@ -40,6 +40,7 @@ import org.springframework.util.Assert;
  * @author Phillip Webb
  * @author Francis Lavoie
  */
+@SuppressWarnings("removal")
 class Connection {
 
 	private static final Log logger = LogFactory.getLog(Connection.class);

module/spring-boot-devtools/src/main/java/org/springframework/boot/devtools/livereload/LiveReloadServer.java

@@ -42,7 +42,9 @@ import org.springframework.util.Assert;
  *
  * @author Phillip Webb
  * @since 1.3.0
+ * @deprecated since 4.1.0 for removal in 4.3.0 with no replacement.
  */
+@Deprecated(since = "4.1.0", forRemoval = true)
 public class LiveReloadServer {
 
 	/**

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

@@ -37,6 +37,7 @@ import org.springframework.util.Assert;
  *
  * @author Phillip Webb
  */
+@SuppressWarnings("removal")
 class DelayedLiveReloadTrigger implements Runnable {
 
 	private static final long SHUTDOWN_TIME = 1000;

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

@@ -36,7 +36,6 @@ import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.boot.devtools.autoconfigure.DevToolsProperties;
 import org.springframework.boot.devtools.autoconfigure.DevToolsProperties.Restart;
-import org.springframework.boot.devtools.autoconfigure.OptionalLiveReloadServer;
 import org.springframework.boot.devtools.autoconfigure.RemoteDevToolsProperties;
 import org.springframework.boot.devtools.autoconfigure.RemoteDevToolsProperties.Proxy;
 import org.springframework.boot.devtools.autoconfigure.TriggerFileFilter;
@@ -46,7 +45,6 @@ import org.springframework.boot.devtools.classpath.ClassPathRestartStrategy;
 import org.springframework.boot.devtools.classpath.PatternClassPathRestartStrategy;
 import org.springframework.boot.devtools.filewatch.FileSystemWatcher;
 import org.springframework.boot.devtools.filewatch.FileSystemWatcherFactory;
-import org.springframework.boot.devtools.livereload.LiveReloadServer;
 import org.springframework.boot.devtools.restart.DefaultRestartInitializer;
 import org.springframework.boot.devtools.restart.RestartScope;
 import org.springframework.boot.devtools.restart.Restarter;
@@ -71,6 +69,7 @@ import org.springframework.util.StringUtils;
  */
 @Configuration(proxyBeanMethods = false)
 @EnableConfigurationProperties(DevToolsProperties.class)
+@SuppressWarnings("removal")
 public class RemoteClientConfiguration implements InitializingBean {
 
 	private static final Log logger = LogFactory.getLog(RemoteClientConfiguration.class);
@@ -152,14 +151,14 @@ public class RemoteClientConfiguration implements InitializingBean {
 		@Bean
 		@RestartScope
 		@ConditionalOnMissingBean
-		LiveReloadServer liveReloadServer() {
-			return new LiveReloadServer(this.properties.getLivereload().getPort(),
-					Restarter.getInstance().getThreadFactory());
+		org.springframework.boot.devtools.livereload.LiveReloadServer liveReloadServer() {
+			return new org.springframework.boot.devtools.livereload.LiveReloadServer(
+					this.properties.getLivereload().getPort(), Restarter.getInstance().getThreadFactory());
 		}
 
 		@Bean
 		ApplicationListener<ClassPathChangedEvent> liveReloadTriggeringClassPathChangedEventListener(
-				OptionalLiveReloadServer optionalLiveReloadServer) {
+				org.springframework.boot.devtools.autoconfigure.OptionalLiveReloadServer optionalLiveReloadServer) {
 			return (event) -> {
 				String url = this.remoteUrl + this.properties.getRemote().getContextPath();
 				this.executor.execute(
@@ -168,8 +167,10 @@ public class RemoteClientConfiguration implements InitializingBean {
 		}
 
 		@Bean
-		OptionalLiveReloadServer optionalLiveReloadServer(ObjectProvider<LiveReloadServer> liveReloadServer) {
-			return new OptionalLiveReloadServer(liveReloadServer.getIfAvailable());
+		org.springframework.boot.devtools.autoconfigure.OptionalLiveReloadServer optionalLiveReloadServer(
+				ObjectProvider<org.springframework.boot.devtools.livereload.LiveReloadServer> liveReloadServer) {
+			return new org.springframework.boot.devtools.autoconfigure.OptionalLiveReloadServer(
+					liveReloadServer.getIfAvailable());
 		}
 
 		final ExecutorService getExecutor() {

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

@@ -73,6 +73,7 @@ import static org.mockito.Mockito.reset;
  * @author Vladimir Tsanev
  */
 @ExtendWith(MockRestarter.class)
+@SuppressWarnings("removal")
 class LocalDevToolsAutoConfigurationTests {
 
 	private @Nullable ConfigurableApplicationContext context;

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

@@ -30,6 +30,7 @@ import static org.mockito.Mockito.never;
  *
  * @author Phillip Webb
  */
+@SuppressWarnings("removal")
 class OptionalLiveReloadServerTests {
 
 	@Test

module/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/livereload/LiveReloadServerTests.java

@@ -83,6 +83,7 @@ import static org.hamcrest.Matchers.not;
  * @author Phillip Webb
  * @author Andy Wilkinson
  */
+@SuppressWarnings("removal")
 class LiveReloadServerTests {
 
 	private static final String HANDSHAKE = "{command: 'hello', "

module/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/remote/client/DelayedLiveReloadTriggerTests.java

@@ -44,6 +44,7 @@ import static org.mockito.Mockito.never;
  * @author Phillip Webb
  */
 @ExtendWith(MockitoExtension.class)
+@SuppressWarnings("removal")
 class DelayedLiveReloadTriggerTests {
 
 	private static final String URL = "http://localhost:8080";

module/spring-boot-devtools/src/test/java/org/springframework/boot/devtools/remote/client/RemoteClientConfigurationTests.java

@@ -104,6 +104,7 @@ class RemoteClientConfigurationTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void liveReloadOnClassPathChanged() {
 		configure("spring.devtools.livereload.enabled:true");
 		Set<ChangedFiles> changeSet = new HashSet<>();
@@ -115,6 +116,7 @@ class RemoteClientConfigurationTests {
 	}
 
 	@Test
+	@SuppressWarnings("removal")
 	void liveReloadDisabledByDefault() {
 		configure();
 		assertThatExceptionOfType(NoSuchBeanDefinitionException.class)
@@ -185,6 +187,7 @@ class RemoteClientConfigurationTests {
 	}
 
 	@Configuration(proxyBeanMethods = false)
+	@SuppressWarnings("removal")
 	static class ClientConfig {
 
 		@Bean