Implement JDK HttpClient based Zipkin sender

Closes gh-39545

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/HttpSender.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -74,7 +74,7 @@ abstract class HttpSender extends BaseHttpSender<URI, byte[]> {
 	 * @param headers headers for the POST request
 	 * @param body list of possibly gzipped, encoded spans.
 	 */
-	abstract void postSpans(URI endpoint, HttpHeaders headers, byte[] body);
+	abstract void postSpans(URI endpoint, HttpHeaders headers, byte[] body) throws IOException;
 
 	HttpHeaders getDefaultHeaders() {
 		HttpHeaders headers = new HttpHeaders();

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurations.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -16,6 +16,9 @@
 
 package org.springframework.boot.actuate.autoconfigure.tracing.zipkin;
 
+import java.net.http.HttpClient;
+import java.net.http.HttpClient.Builder;
+
 import brave.Tag;
 import brave.Tags;
 import brave.handler.MutableSpan;
@@ -53,7 +56,7 @@ class ZipkinConfigurations {
 
 	@Configuration(proxyBeanMethods = false)
 	@Import({ UrlConnectionSenderConfiguration.class, WebClientSenderConfiguration.class,
-			RestTemplateSenderConfiguration.class })
+			RestTemplateSenderConfiguration.class, HttpClientSenderConfiguration.class })
 	static class SenderConfiguration {
 
 	}
@@ -90,6 +93,7 @@ class ZipkinConfigurations {
 
 		@Bean
 		@ConditionalOnMissingBean(BytesMessageSender.class)
+		@SuppressWarnings("removal")
 		ZipkinRestTemplateSender restTemplateSender(ZipkinProperties properties, Encoding encoding,
 				ObjectProvider<ZipkinRestTemplateBuilderCustomizer> customizers,
 				ObjectProvider<ZipkinConnectionDetails> connectionDetailsProvider,
@@ -106,6 +110,7 @@ class ZipkinConfigurations {
 					restTemplateBuilder.build());
 		}
 
+		@SuppressWarnings("removal")
 		private RestTemplateBuilder applyCustomizers(RestTemplateBuilder restTemplateBuilder,
 				ObjectProvider<ZipkinRestTemplateBuilderCustomizer> customizers) {
 			Iterable<ZipkinRestTemplateBuilderCustomizer> orderedCustomizers = () -> customizers.orderedStream()
@@ -126,6 +131,7 @@ class ZipkinConfigurations {
 
 		@Bean
 		@ConditionalOnMissingBean(BytesMessageSender.class)
+		@SuppressWarnings("removal")
 		ZipkinWebClientSender webClientSender(ZipkinProperties properties, Encoding encoding,
 				ObjectProvider<ZipkinWebClientBuilderCustomizer> customizers,
 				ObjectProvider<ZipkinConnectionDetails> connectionDetailsProvider,
@@ -142,6 +148,29 @@ class ZipkinConfigurations {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	@ConditionalOnClass(HttpClient.class)
+	@EnableConfigurationProperties(ZipkinProperties.class)
+	static class HttpClientSenderConfiguration {
+
+		@Bean
+		@ConditionalOnMissingBean(BytesMessageSender.class)
+		ZipkinHttpClientSender httpClientSender(ZipkinProperties properties, Encoding encoding,
+				ObjectProvider<ZipkinHttpClientBuilderCustomizer> customizers,
+				ObjectProvider<ZipkinConnectionDetails> connectionDetailsProvider,
+				ObjectProvider<HttpEndpointSupplier.Factory> endpointSupplierFactoryProvider) {
+			ZipkinConnectionDetails connectionDetails = connectionDetailsProvider
+				.getIfAvailable(() -> new PropertiesZipkinConnectionDetails(properties));
+			HttpEndpointSupplier.Factory endpointSupplierFactory = endpointSupplierFactoryProvider
+				.getIfAvailable(HttpEndpointSuppliers::constantFactory);
+			Builder httpClientBuilder = HttpClient.newBuilder().connectTimeout(properties.getConnectTimeout());
+			customizers.orderedStream().forEach((customizer) -> customizer.customize(httpClientBuilder));
+			return new ZipkinHttpClientSender(encoding, endpointSupplierFactory, connectionDetails.getSpanEndpoint(),
+					httpClientBuilder.build(), properties.getReadTimeout());
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	@ConditionalOnClass(AsyncZipkinSpanHandler.class)
 	static class BraveConfiguration {

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinHttpClientBuilderCustomizer.java

@@ -0,0 +1,37 @@
+/*
+ * Copyright 2012-2024 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.autoconfigure.tracing.zipkin;
+
+import java.net.http.HttpClient;
+
+/**
+ * Callback interface that can be implemented by beans wishing to customize the
+ * {@link HttpClient.Builder} used to send spans to Zipkin.
+ *
+ * @author Moritz Halbritter
+ * @since 3.3.0
+ */
+@FunctionalInterface
+public interface ZipkinHttpClientBuilderCustomizer {
+
+	/**
+	 * Customize the http client builder.
+	 * @param httpClient the http client builder to customize
+	 */
+	void customize(HttpClient.Builder httpClient);
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinHttpClientSender.java

@@ -0,0 +1,71 @@
+/*
+ * Copyright 2012-2024 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.autoconfigure.tracing.zipkin;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpRequest.BodyPublishers;
+import java.net.http.HttpRequest.Builder;
+import java.net.http.HttpResponse;
+import java.net.http.HttpResponse.BodyHandlers;
+import java.time.Duration;
+
+import zipkin2.reporter.Encoding;
+import zipkin2.reporter.HttpEndpointSupplier.Factory;
+
+import org.springframework.http.HttpHeaders;
+
+/**
+ * A {@link HttpSender} which uses the JDK {@link HttpClient} for HTTP communication.
+ *
+ * @author Moritz Halbritter
+ */
+class ZipkinHttpClientSender extends HttpSender {
+
+	private final HttpClient httpClient;
+
+	private final Duration readTimeout;
+
+	ZipkinHttpClientSender(Encoding encoding, Factory endpointSupplierFactory, String endpoint, HttpClient httpClient,
+			Duration readTimeout) {
+		super(encoding, endpointSupplierFactory, endpoint);
+		this.httpClient = httpClient;
+		this.readTimeout = readTimeout;
+	}
+
+	@Override
+	void postSpans(URI endpoint, HttpHeaders headers, byte[] body) throws IOException {
+		Builder request = HttpRequest.newBuilder()
+			.POST(BodyPublishers.ofByteArray(body))
+			.uri(endpoint)
+			.timeout(this.readTimeout);
+		headers.forEach((key, values) -> values.forEach((value) -> request.header(key, value)));
+		try {
+			HttpResponse<Void> response = this.httpClient.send(request.build(), BodyHandlers.discarding());
+			if (response.statusCode() / 100 != 2) {
+				throw new IOException("Expected HTTP status 2xx, got %d".formatted(response.statusCode()));
+			}
+		}
+		catch (InterruptedException ex) {
+			Thread.currentThread().interrupt();
+			throw new IOException("Got interrupted while sending spans", ex);
+		}
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinRestTemplateBuilderCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -24,8 +24,11 @@ import org.springframework.boot.web.client.RestTemplateBuilder;
  *
  * @author Marcin Grzejszczak
  * @since 3.0.0
+ * @deprecated since 3.3.0 for removal in 3.5.0 in favor of
+ * {@link ZipkinHttpClientBuilderCustomizer}
  */
 @FunctionalInterface
+@Deprecated(since = "3.3.0", forRemoval = true)
 public interface ZipkinRestTemplateBuilderCustomizer {
 
 	/**

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinRestTemplateSender.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -32,6 +32,7 @@ import org.springframework.web.client.RestTemplate;
  * @author Moritz Halbritter
  * @author Stefan Bratanov
  */
+@Deprecated(since = "3.3.0", forRemoval = true)
 class ZipkinRestTemplateSender extends HttpSender {
 
 	private final RestTemplate restTemplate;

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinWebClientBuilderCustomizer.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2022 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -25,8 +25,11 @@ import org.springframework.web.reactive.function.client.WebClient.Builder;
  *
  * @author Marcin Grzejszczak
  * @since 3.0.0
+ * @deprecated since 3.3.0 for removal in 3.5.0 in favor of
+ * {@link ZipkinHttpClientBuilderCustomizer}
  */
 @FunctionalInterface
+@Deprecated(since = "3.3.0", forRemoval = true)
 public interface ZipkinWebClientBuilderCustomizer {
 
 	/**

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinWebClientSender.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -31,6 +31,7 @@ import org.springframework.web.reactive.function.client.WebClient;
  * @author Stefan Bratanov
  * @author Moritz Halbritter
  */
+@Deprecated(since = "3.3.0", forRemoval = true)
 class ZipkinWebClientSender extends HttpSender {
 
 	private final WebClient webClient;

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinConfigurationsSenderConfigurationTests.java

@@ -50,6 +50,7 @@ import static org.mockito.Mockito.mock;
  *
  * @author Moritz Halbritter
  */
+@SuppressWarnings("removal")
 class ZipkinConfigurationsSenderConfigurationTests {
 
 	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
@@ -70,6 +71,20 @@ class ZipkinConfigurationsSenderConfigurationTests {
 		});
 	}
 
+	@Test
+	void shouldUseHttpClientIfUrlSenderIsNotAvailable() {
+		this.contextRunner.withUserConfiguration(HttpClientConfiguration.class)
+			.withClassLoader(new FilteredClassLoader("zipkin2.reporter.urlconnection", "org.springframework.web.client",
+					"org.springframework.web.reactive.function.client"))
+			.run((context) -> {
+				assertThat(context).doesNotHaveBean(URLConnectionSender.class);
+				assertThat(context).hasSingleBean(BytesMessageSender.class);
+				assertThat(context).hasSingleBean(ZipkinHttpClientSender.class);
+				then(context.getBean(ZipkinHttpClientBuilderCustomizer.class)).should()
+					.customize(ArgumentMatchers.any());
+			});
+	}
+
 	@Test
 	void shouldPreferWebClientSenderIfWebApplicationIsReactiveAndUrlSenderIsNotAvailable() {
 		this.reactiveContextRunner.withUserConfiguration(RestTemplateConfiguration.class, WebClientConfiguration.class)
@@ -220,6 +235,16 @@ class ZipkinConfigurationsSenderConfigurationTests {
 
 	}
 
+	@Configuration(proxyBeanMethods = false)
+	private static final class HttpClientConfiguration {
+
+		@Bean
+		ZipkinHttpClientBuilderCustomizer httpClientBuilderCustomizer() {
+			return mock(ZipkinHttpClientBuilderCustomizer.class);
+		}
+
+	}
+
 	@Configuration(proxyBeanMethods = false)
 	private static final class CustomConfiguration {
 

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinHttpClientSenderTests.java

@@ -0,0 +1,210 @@
+/*
+ * Copyright 2012-2024 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.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.boot.actuate.autoconfigure.tracing.zipkin;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.time.Duration;
+import java.util.Base64;
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
+import java.util.function.Consumer;
+
+import okhttp3.mockwebserver.MockResponse;
+import okhttp3.mockwebserver.MockWebServer;
+import okhttp3.mockwebserver.QueueDispatcher;
+import okhttp3.mockwebserver.RecordedRequest;
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import zipkin2.reporter.BytesMessageSender;
+import zipkin2.reporter.Encoding;
+import zipkin2.reporter.HttpEndpointSupplier;
+import zipkin2.reporter.HttpEndpointSuppliers;
+
+import org.springframework.http.HttpHeaders;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatException;
+import static org.assertj.core.api.Assertions.assertThatIOException;
+
+/**
+ * Tests for {@link ZipkinHttpClientSender}.
+ *
+ * @author Moritz Halbritter
+ */
+class ZipkinHttpClientSenderTests extends ZipkinHttpSenderTests {
+
+	private static ClearableDispatcher dispatcher;
+
+	private static MockWebServer mockBackEnd;
+
+	private static String zipkinUrl;
+
+	@BeforeAll
+	static void beforeAll() throws IOException {
+		dispatcher = new ClearableDispatcher();
+		mockBackEnd = new MockWebServer();
+		mockBackEnd.setDispatcher(dispatcher);
+		mockBackEnd.start();
+		zipkinUrl = mockBackEnd.url("/api/v2/spans").toString();
+	}
+
+	@AfterAll
+	static void afterAll() throws IOException {
+		mockBackEnd.shutdown();
+	}
+
+	@Override
+	@BeforeEach
+	void beforeEach() throws Exception {
+		super.beforeEach();
+		clearResponses();
+		clearRequests();
+	}
+
+	@Override
+	BytesMessageSender createSender() {
+		return createSender(Encoding.JSON, Duration.ofSeconds(10));
+	}
+
+	ZipkinHttpClientSender createSender(Encoding encoding, Duration timeout) {
+		return createSender(HttpEndpointSuppliers.constantFactory(), encoding, timeout);
+	}
+
+	ZipkinHttpClientSender createSender(HttpEndpointSupplier.Factory endpointSupplierFactory, Encoding encoding,
+			Duration timeout) {
+		HttpClient httpClient = HttpClient.newBuilder().connectTimeout(timeout).build();
+		return new ZipkinHttpClientSender(encoding, endpointSupplierFactory, zipkinUrl, httpClient, timeout);
+	}
+
+	@Test
+	void sendShouldSendSpansToZipkin() throws IOException, InterruptedException {
+		mockBackEnd.enqueue(new MockResponse());
+		List<byte[]> encodedSpans = List.of(toByteArray("span1"), toByteArray("span2"));
+		this.sender.send(encodedSpans);
+		requestAssertions((request) -> {
+			assertThat(request.getMethod()).isEqualTo("POST");
+			assertThat(request.getHeader("Content-Type")).isEqualTo("application/json");
+			assertThat(request.getBody().readUtf8()).isEqualTo("[span1,span2]");
+		});
+	}
+
+	@Test
+	void sendShouldSendSpansToZipkinInProto3() throws IOException, InterruptedException {
+		mockBackEnd.enqueue(new MockResponse());
+		List<byte[]> encodedSpans = List.of(toByteArray("span1"), toByteArray("span2"));
+		try (BytesMessageSender sender = createSender(Encoding.PROTO3, Duration.ofSeconds(10))) {
+			sender.send(encodedSpans);
+		}
+		requestAssertions((request) -> {
+			assertThat(request.getMethod()).isEqualTo("POST");
+			assertThat(request.getHeader("Content-Type")).isEqualTo("application/x-protobuf");
+			assertThat(request.getBody().readUtf8()).isEqualTo("span1span2");
+		});
+	}
+
+	/**
+	 * This tests that a dynamic {@linkplain HttpEndpointSupplier} updates are visible to
+	 * {@link HttpSender#postSpans(URI, HttpHeaders, byte[])}.
+	 */
+	@Test
+	void sendUsesDynamicEndpoint() throws Exception {
+		mockBackEnd.enqueue(new MockResponse());
+		mockBackEnd.enqueue(new MockResponse());
+		AtomicInteger suffix = new AtomicInteger();
+		try (BytesMessageSender sender = createSender((e) -> new HttpEndpointSupplier() {
+			@Override
+			public String get() {
+				return zipkinUrl + "/" + suffix.incrementAndGet();
+			}
+
+			@Override
+			public void close() {
+			}
+		}, Encoding.JSON, Duration.ofSeconds(10))) {
+			sender.send(Collections.emptyList());
+			sender.send(Collections.emptyList());
+		}
+		assertThat(mockBackEnd.takeRequest().getPath()).endsWith("/1");
+		assertThat(mockBackEnd.takeRequest().getPath()).endsWith("/2");
+	}
+
+	@Test
+	void sendShouldHandleHttpFailures() throws InterruptedException {
+		mockBackEnd.enqueue(new MockResponse().setResponseCode(500));
+		assertThatException().isThrownBy(() -> this.sender.send(Collections.emptyList()))
+			.withMessageContaining("Expected HTTP status 2xx, got 500");
+		requestAssertions((request) -> assertThat(request.getMethod()).isEqualTo("POST"));
+	}
+
+	@Test
+	void sendShouldCompressData() throws IOException, InterruptedException {
+		String uncompressed = "a".repeat(10000);
+		// This is gzip compressed 10000 times 'a'
+		byte[] compressed = Base64.getDecoder()
+			.decode("H4sIAAAAAAAA/+3BMQ0AAAwDIKFLj/k3UR8NcA8AAAAAAAAAAAADUsAZfeASJwAA");
+		mockBackEnd.enqueue(new MockResponse());
+		this.sender.send(List.of(toByteArray(uncompressed)));
+		requestAssertions((request) -> {
+			assertThat(request.getMethod()).isEqualTo("POST");
+			assertThat(request.getHeader("Content-Type")).isEqualTo("application/json");
+			assertThat(request.getHeader("Content-Encoding")).isEqualTo("gzip");
+			assertThat(request.getBody().readByteArray()).isEqualTo(compressed);
+		});
+	}
+
+	@Test
+	void shouldTimeout() throws IOException {
+		try (BytesMessageSender sender = createSender(Encoding.JSON, Duration.ofMillis(1))) {
+			MockResponse response = new MockResponse().setResponseCode(200).setHeadersDelay(100, TimeUnit.MILLISECONDS);
+			mockBackEnd.enqueue(response);
+			assertThatIOException().isThrownBy(() -> sender.send(Collections.emptyList()))
+				.withMessageContaining("timed out");
+		}
+	}
+
+	private void requestAssertions(Consumer<RecordedRequest> assertions) throws InterruptedException {
+		RecordedRequest request = mockBackEnd.takeRequest();
+		assertThat(request).satisfies(assertions);
+	}
+
+	private static void clearRequests() throws InterruptedException {
+		RecordedRequest request;
+		do {
+			request = mockBackEnd.takeRequest(0, TimeUnit.SECONDS);
+		}
+		while (request != null);
+	}
+
+	private static void clearResponses() {
+		dispatcher.clear();
+	}
+
+	private static final class ClearableDispatcher extends QueueDispatcher {
+
+		void clear() {
+			getResponseQueue().clear();
+		}
+
+	}
+
+}

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinRestTemplateSenderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -49,6 +49,7 @@ import static org.springframework.test.web.client.response.MockRestResponseCreat
  * @author Moritz Halbritter
  * @author Stefan Bratanov
  */
+@SuppressWarnings("removal")
 class ZipkinRestTemplateSenderTests extends ZipkinHttpSenderTests {
 
 	private static final String ZIPKIN_URL = "http://localhost:9411/api/v2/spans";

spring-boot-project/spring-boot-actuator-autoconfigure/src/test/java/org/springframework/boot/actuate/autoconfigure/tracing/zipkin/ZipkinWebClientSenderTests.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2012-2023 the original author or authors.
+ * Copyright 2012-2024 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.
@@ -51,6 +51,7 @@ import static org.assertj.core.api.Assertions.assertThatException;
  *
  * @author Stefan Bratanov
  */
+@SuppressWarnings("removal")
 class ZipkinWebClientSenderTests extends ZipkinHttpSenderTests {
 
 	private static ClearableDispatcher dispatcher;