Upgrade to Spring Framework 6.1.0-M1

Closes gh-35977
Closes gh-35980

buildSrc/build.gradle

@@ -14,15 +14,10 @@ new File(new File("$projectDir").parentFile, "gradle.properties").withInputStrea
 	def properties = new Properties()
 	properties.load(it)
 	ext.set("kotlinVersion", properties["kotlinVersion"])
-	ext.set("springFrameworkVersion", properties["springFrameworkVersion"])
-	if (properties["springFrameworkVersion"].contains("-")) {
-		repositories {
-			maven { url "https://repo.spring.io/milestone" }
-			maven { url "https://repo.spring.io/snapshot" }
-		}
-	}
 }
 
+ext.set("springFrameworkVersion", "6.0.10")
+
 sourceCompatibility = 17
 targetCompatibility = 17
 

gradle.properties

@@ -6,7 +6,7 @@ org.gradle.jvmargs=-Xmx2g -Dfile.encoding=UTF-8
 
 kotlinVersion=1.8.22
 nativeBuildToolsVersion=0.9.23
-springFrameworkVersion=6.0.10
+springFrameworkVersion=6.1.0-M1
 tomcatVersion=10.1.10
 
 kotlin.stdlib.default.dependency=false

spring-boot-project/spring-boot-actuator-autoconfigure/src/main/java/org/springframework/boot/actuate/autoconfigure/observation/web/reactive/OrderedServerHttpObservationFilter.java

@@ -28,6 +28,7 @@ import org.springframework.web.filter.reactive.ServerHttpObservationFilter;
  *
  * @author Moritz Halbritter
  */
+@SuppressWarnings({ "deprecation", "removal" })
 class OrderedServerHttpObservationFilter extends ServerHttpObservationFilter implements OrderedWebFilter {
 
 	private final int order;

spring-boot-project/spring-boot-test/src/main/java/org/springframework/boot/test/web/client/TestRestTemplate.java

@@ -1021,9 +1021,6 @@ public class TestRestTemplate {
 			if (settings.connectTimeout() != null) {
 				setConnectTimeout((int) settings.connectTimeout().toMillis());
 			}
-			if (settings.bufferRequestBody() != null) {
-				setBufferRequestBody(settings.bufferRequestBody());
-			}
 		}
 
 		private HttpClient createHttpClient(Duration readTimeout, boolean ssl) {

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/SpringBootContextLoaderTests.java

@@ -255,7 +255,7 @@ class SpringBootContextLoaderTests {
 	private Map<String, Object> getMergedContextConfigurationProperties(Class<?> testClass) {
 		TestContext context = new ExposedTestContextManager(testClass).getExposedTestContext();
 		MergedContextConfiguration config = (MergedContextConfiguration) ReflectionTestUtils.getField(context,
-				"mergedContextConfiguration");
+				"mergedConfig");
 		return TestPropertySourceUtils.convertInlinedPropertiesToMap(config.getPropertySourceProperties());
 	}
 

spring-boot-project/spring-boot-test/src/test/java/org/springframework/boot/test/context/bootstrap/SpringBootTestContextBootstrapperTests.java

@@ -110,7 +110,7 @@ class SpringBootTestContextBootstrapperTests {
 	}
 
 	private MergedContextConfiguration getMergedContextConfiguration(TestContext context) {
-		return (MergedContextConfiguration) ReflectionTestUtils.getField(context, "mergedContextConfiguration");
+		return (MergedContextConfiguration) ReflectionTestUtils.getField(context, "mergedConfig");
 	}
 
 	@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)

spring-boot-project/spring-boot-tools/spring-boot-buildpack-platform/build.gradle

@@ -14,6 +14,11 @@ configurations.all {
 			if (dependency.requested.group.startsWith("com.fasterxml.jackson")) {
 				dependency.useVersion("2.14.2")
 			}
+			// Downgrade Spring Framework as Gradle cannot cope with 6.1.0-M1's
+			// multi-version jar files with bytecode in META-INF/versions/21
+			if (dependency.requested.group.equals("org.springframework")) {
+				dependency.useVersion("6.0.10")
+			}
 		}
 	}
 }

spring-boot-project/spring-boot-tools/spring-boot-gradle-plugin/build.gradle

@@ -23,6 +23,11 @@ configurations {
 				if (dependency.requested.group.startsWith("com.fasterxml.jackson")) {
 					dependency.useVersion("2.14.2")
 				}
+				// Downgrade Spring Framework as Gradle cannot cope with 6.1.0-M1's
+				// multi-version jar files with bytecode in META-INF/versions/21
+				if (dependency.requested.group.equals("org.springframework")) {
+					dependency.useVersion("6.0.10")
+				}
 			}
 		}
 	}

spring-boot-project/spring-boot-tools/spring-boot-loader-tools/build.gradle

@@ -17,6 +17,17 @@ configurations {
 		extendsFrom dependencyManagement
 		transitive = false
 	}
+	all {
+		resolutionStrategy {
+			eachDependency { dependency ->
+				// Downgrade Spring Framework as Gradle cannot cope with 6.1.0-M1's
+				// multi-version jar files with bytecode in META-INF/versions/21
+				if (dependency.requested.group.equals("org.springframework")) {
+					dependency.useVersion("6.0.10")
+				}
+			}
+		}
+	}
 }
 
 dependencies {

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/client/ClientHttpRequestFactories.java

@@ -151,7 +151,6 @@ public final class ClientHttpRequestFactories {
 					settings.sslBundle());
 			PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
 			map.from(settings::connectTimeout).asInt(Duration::toMillis).to(requestFactory::setConnectTimeout);
-			map.from(settings::bufferRequestBody).to(requestFactory::setBufferRequestBody);
 			return requestFactory;
 		}
 
@@ -187,8 +186,6 @@ public final class ClientHttpRequestFactories {
 	static class OkHttp {
 
 		static OkHttp3ClientHttpRequestFactory get(ClientHttpRequestFactorySettings settings) {
-			Assert.state(settings.bufferRequestBody() == null,
-					() -> "OkHttp3ClientHttpRequestFactory does not support request body buffering");
 			OkHttp3ClientHttpRequestFactory requestFactory = createRequestFactory(settings.sslBundle());
 			PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
 			map.from(settings::connectTimeout).asInt(Duration::toMillis).to(requestFactory::setConnectTimeout);
@@ -227,7 +224,6 @@ public final class ClientHttpRequestFactories {
 			PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
 			map.from(settings::readTimeout).asInt(Duration::toMillis).to(requestFactory::setReadTimeout);
 			map.from(settings::connectTimeout).asInt(Duration::toMillis).to(requestFactory::setConnectTimeout);
-			map.from(settings::bufferRequestBody).to(requestFactory::setBufferRequestBody);
 			return requestFactory;
 		}
 
@@ -274,8 +270,6 @@ public final class ClientHttpRequestFactories {
 			PropertyMapper map = PropertyMapper.get().alwaysApplyingWhenNonNull();
 			map.from(settings::connectTimeout).to((connectTimeout) -> setConnectTimeout(unwrapped, connectTimeout));
 			map.from(settings::readTimeout).to((readTimeout) -> setReadTimeout(unwrapped, readTimeout));
-			map.from(settings::bufferRequestBody)
-				.to((bufferRequestBody) -> setBufferRequestBody(unwrapped, bufferRequestBody));
 		}
 
 		private static ClientHttpRequestFactory unwrapRequestFactoryIfNecessary(
@@ -305,11 +299,6 @@ public final class ClientHttpRequestFactories {
 			invoke(factory, method, timeout);
 		}
 
-		private static void setBufferRequestBody(ClientHttpRequestFactory factory, boolean bufferRequestBody) {
-			Method method = findMethod(factory, "setBufferRequestBody", boolean.class);
-			invoke(factory, method, bufferRequestBody);
-		}
-
 		private static Method findMethod(ClientHttpRequestFactory requestFactory, String methodName,
 				Class<?>... parameters) {
 			Method method = ReflectionUtils.findMethod(requestFactory.getClass(), methodName, parameters);

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/client/ClientHttpRequestFactoriesRuntimeHints.java

@@ -69,7 +69,6 @@ class ClientHttpRequestFactoriesRuntimeHints implements RuntimeHintsRegistrar {
 			Class<? extends ClientHttpRequestFactory> requestFactoryType) {
 		registerMethod(hints, requestFactoryType, "setConnectTimeout", int.class);
 		registerMethod(hints, requestFactoryType, "setReadTimeout", int.class);
-		registerMethod(hints, requestFactoryType, "setBufferRequestBody", boolean.class);
 	}
 
 	private void registerMethod(ReflectionHints hints, Class<? extends ClientHttpRequestFactory> requestFactoryType,

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/client/ClientHttpRequestFactorySettings.java

@@ -26,7 +26,6 @@ import org.springframework.http.client.ClientHttpRequestFactory;
  *
  * @param connectTimeout the connect timeout
  * @param readTimeout the read timeout
- * @param bufferRequestBody if request body buffering is used
  * @param sslBundle the SSL bundle providing SSL configuration
  * @author Andy Wilkinson
  * @author Phillip Webb
@@ -34,8 +33,7 @@ import org.springframework.http.client.ClientHttpRequestFactory;
  * @since 3.0.0
  * @see ClientHttpRequestFactories
  */
-public record ClientHttpRequestFactorySettings(Duration connectTimeout, Duration readTimeout, Boolean bufferRequestBody,
-		SslBundle sslBundle) {
+public record ClientHttpRequestFactorySettings(Duration connectTimeout, Duration readTimeout, SslBundle sslBundle) {
 
 	/**
 	 * Use defaults for the {@link ClientHttpRequestFactory} which can differ depending on
@@ -48,15 +46,29 @@ public record ClientHttpRequestFactorySettings(Duration connectTimeout, Duration
 	 * Create a new {@link ClientHttpRequestFactorySettings} instance.
 	 * @param connectTimeout the connection timeout
 	 * @param readTimeout the read timeout
-	 * @param bufferRequestBody the bugger request body
-	 * @param sslBundle the ssl bundle
-	 * @since 3.1.0
+	 * @param bufferRequestBody if request body buffering is used
+	 * @deprecated since 3.2.0 for removal in 3.4.0 as support for buffering has been
+	 * removed in Spring Framework 6.1
 	 */
-	public ClientHttpRequestFactorySettings {
+	@Deprecated(since = "3.2.0", forRemoval = true)
+	public ClientHttpRequestFactorySettings(Duration connectTimeout, Duration readTimeout, Boolean bufferRequestBody) {
+		this(connectTimeout, readTimeout, (SslBundle) null);
 	}
 
-	public ClientHttpRequestFactorySettings(Duration connectTimeout, Duration readTimeout, Boolean bufferRequestBody) {
-		this(connectTimeout, readTimeout, bufferRequestBody, null);
+	/**
+	 * Create a new {@link ClientHttpRequestFactorySettings} instance.
+	 * @param connectTimeout the connection timeout
+	 * @param readTimeout the read timeout
+	 * @param bufferRequestBody if request body buffering is used
+	 * @param sslBundle the ssl bundle
+	 * @since 3.1.0
+	 * @deprecated since 3.2.0 for removal in 3.4.0 as support for buffering has been
+	 * removed in Spring Framework 6.1
+	 */
+	@Deprecated(since = "3.2.0", forRemoval = true)
+	public ClientHttpRequestFactorySettings(Duration connectTimeout, Duration readTimeout, Boolean bufferRequestBody,
+			SslBundle sslBundle) {
+		this(connectTimeout, readTimeout, sslBundle);
 	}
 
 	/**
@@ -66,8 +78,7 @@ public record ClientHttpRequestFactorySettings(Duration connectTimeout, Duration
 	 * @return a new {@link ClientHttpRequestFactorySettings} instance
 	 */
 	public ClientHttpRequestFactorySettings withConnectTimeout(Duration connectTimeout) {
-		return new ClientHttpRequestFactorySettings(connectTimeout, this.readTimeout, this.bufferRequestBody,
-				this.sslBundle);
+		return new ClientHttpRequestFactorySettings(connectTimeout, this.readTimeout, this.sslBundle);
 	}
 
 	/**
@@ -78,19 +89,19 @@ public record ClientHttpRequestFactorySettings(Duration connectTimeout, Duration
 	 */
 
 	public ClientHttpRequestFactorySettings withReadTimeout(Duration readTimeout) {
-		return new ClientHttpRequestFactorySettings(this.connectTimeout, readTimeout, this.bufferRequestBody,
-				this.sslBundle);
+		return new ClientHttpRequestFactorySettings(this.connectTimeout, readTimeout, this.sslBundle);
 	}
 
 	/**
-	 * Return a new {@link ClientHttpRequestFactorySettings} instance with an updated
-	 * buffer request body setting.
+	 * Has no effect as support for buffering has been removed in Spring Framework 6.1.
 	 * @param bufferRequestBody the new buffer request body setting
 	 * @return a new {@link ClientHttpRequestFactorySettings} instance
+	 * @deprecated since 3.2.0 for removal in 3.4.0 as support for buffering has been
+	 * removed in Spring Framework 6.1
 	 */
+	@Deprecated(since = "3.2.0", forRemoval = true)
 	public ClientHttpRequestFactorySettings withBufferRequestBody(Boolean bufferRequestBody) {
-		return new ClientHttpRequestFactorySettings(this.connectTimeout, this.readTimeout, bufferRequestBody,
-				this.sslBundle);
+		return this;
 	}
 
 	/**
@@ -101,8 +112,18 @@ public record ClientHttpRequestFactorySettings(Duration connectTimeout, Duration
 	 * @since 3.1.0
 	 */
 	public ClientHttpRequestFactorySettings withSslBundle(SslBundle sslBundle) {
-		return new ClientHttpRequestFactorySettings(this.connectTimeout, this.readTimeout, this.bufferRequestBody,
-				sslBundle);
+		return new ClientHttpRequestFactorySettings(this.connectTimeout, this.readTimeout, sslBundle);
+	}
+
+	/**
+	 * Returns whether request body buffering is used.
+	 * @return whether request body buffering is used
+	 * @deprecated since 3.2.0 for removal in 3.4.0 as support for buffering has been
+	 * removed in Spring Framework 6.1
+	 */
+	@Deprecated(since = "3.2.0", forRemoval = true)
+	public Boolean bufferRequestBody() {
+		return null;
 	}
 
 }

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/web/client/RestTemplateBuilder.java

@@ -440,19 +440,18 @@ public class RestTemplateBuilder {
 	}
 
 	/**
-	 * Sets if the underlying {@link ClientHttpRequestFactory} should buffer the
-	 * {@linkplain ClientHttpRequest#getBody() request body} internally.
+	 * Has no effect as support for buffering has been removed in Spring Framework 6.1.
 	 * @param bufferRequestBody value of the bufferRequestBody parameter
 	 * @return a new builder instance.
 	 * @since 2.2.0
+	 * @deprecated since 3.2.0 for removal in 3.4.0 as support for buffering has been
+	 * removed in Spring Framework 6.1
 	 * @see SimpleClientHttpRequestFactory#setBufferRequestBody(boolean)
 	 * @see HttpComponentsClientHttpRequestFactory#setBufferRequestBody(boolean)
 	 */
+	@Deprecated(since = "3.2.0", forRemoval = true)
 	public RestTemplateBuilder setBufferRequestBody(boolean bufferRequestBody) {
-		return new RestTemplateBuilder(this.requestFactorySettings.withBufferRequestBody(bufferRequestBody),
-				this.detectRequestFactory, this.rootUri, this.messageConverters, this.interceptors, this.requestFactory,
-				this.uriTemplateHandler, this.errorHandler, this.basicAuthentication, this.defaultHeaders,
-				this.customizers, this.requestCustomizers);
+		return this;
 	}
 
 	/**

spring-boot-project/spring-boot/src/main/java/org/springframework/boot/webservices/client/HttpWebServiceMessageSenderBuilder.java

@@ -113,7 +113,7 @@ public class HttpWebServiceMessageSenderBuilder {
 
 	private ClientHttpRequestFactory getRequestFactory() {
 		ClientHttpRequestFactorySettings settings = new ClientHttpRequestFactorySettings(this.connectTimeout,
-				this.readTimeout, null, this.sslBundle);
+				this.readTimeout, this.sslBundle);
 		return (this.requestFactory != null) ? this.requestFactory.apply(settings)
 				: ClientHttpRequestFactories.get(settings);
 	}

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/client/ClientHttpRequestFactoriesOkHttp3Tests.java

@@ -27,7 +27,6 @@ import org.springframework.http.client.OkHttp3ClientHttpRequestFactory;
 import org.springframework.test.util.ReflectionTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 
 /**
  * Tests for {@link ClientHttpRequestFactories} when OkHttp 3 is the predominant HTTP
@@ -50,12 +49,6 @@ class ClientHttpRequestFactoriesOkHttp3Tests
 			.startsWith("okhttp-3.");
 	}
 
-	@Test
-	void getFailsWhenBufferRequestBodyIsEnabled() {
-		assertThatIllegalStateException().isThrownBy(() -> ClientHttpRequestFactories
-			.get(ClientHttpRequestFactorySettings.DEFAULTS.withBufferRequestBody(true)));
-	}
-
 	@Override
 	protected long connectTimeout(OkHttp3ClientHttpRequestFactory requestFactory) {
 		return ((OkHttpClient) ReflectionTestUtils.getField(requestFactory, "client")).connectTimeoutMillis();

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/client/ClientHttpRequestFactoriesOkHttp4Tests.java

@@ -26,7 +26,6 @@ import org.springframework.http.client.OkHttp3ClientHttpRequestFactory;
 import org.springframework.test.util.ReflectionTestUtils;
 
 import static org.assertj.core.api.Assertions.assertThat;
-import static org.assertj.core.api.Assertions.assertThatIllegalStateException;
 
 /**
  * Tests for {@link ClientHttpRequestFactories} when OkHttp 4 is the predominant HTTP
@@ -48,12 +47,6 @@ class ClientHttpRequestFactoriesOkHttp4Tests
 			.startsWith("okhttp-4.");
 	}
 
-	@Test
-	void getFailsWhenBufferRequestBodyIsEnabled() {
-		assertThatIllegalStateException().isThrownBy(() -> ClientHttpRequestFactories
-			.get(ClientHttpRequestFactorySettings.DEFAULTS.withBufferRequestBody(true)));
-	}
-
 	@Override
 	protected long connectTimeout(OkHttp3ClientHttpRequestFactory requestFactory) {
 		return ((OkHttpClient) ReflectionTestUtils.getField(requestFactory, "client")).connectTimeoutMillis();

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/client/ClientHttpRequestFactoriesRuntimeHintsTests.java

@@ -59,12 +59,6 @@ class ClientHttpRequestFactoriesRuntimeHintsTests {
 		assertThat(reflection
 			.onMethod(method(HttpComponentsClientHttpRequestFactory.class, "setConnectTimeout", int.class)))
 			.accepts(hints);
-		assertThat(
-				reflection.onMethod(method(HttpComponentsClientHttpRequestFactory.class, "setReadTimeout", int.class)))
-			.accepts(hints);
-		assertThat(reflection
-			.onMethod(method(HttpComponentsClientHttpRequestFactory.class, "setBufferRequestBody", boolean.class)))
-			.accepts(hints);
 	}
 
 	@Test
@@ -88,9 +82,6 @@ class ClientHttpRequestFactoriesRuntimeHintsTests {
 			.accepts(hints);
 		assertThat(reflection.onMethod(method(SimpleClientHttpRequestFactory.class, "setReadTimeout", int.class)))
 			.accepts(hints);
-		assertThat(reflection
-			.onMethod(method(SimpleClientHttpRequestFactory.class, "setBufferRequestBody", boolean.class)))
-			.accepts(hints);
 	}
 
 	private static Method method(Class<?> target, String name, Class<?>... parameterTypes) {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/client/ClientHttpRequestFactoriesTests.java

@@ -100,14 +100,6 @@ class ClientHttpRequestFactoriesTests {
 			.isEqualTo(Duration.ofSeconds(90).toMillis());
 	}
 
-	@Test
-	void getOfUnknownTypeWithBodyBufferingCreatesFactoryAndConfiguresBodyBuffering() {
-		ClientHttpRequestFactory requestFactory = ClientHttpRequestFactories.get(TestClientHttpRequestFactory.class,
-				ClientHttpRequestFactorySettings.DEFAULTS.withBufferRequestBody(true));
-		assertThat(requestFactory).isInstanceOf(TestClientHttpRequestFactory.class);
-		assertThat(((TestClientHttpRequestFactory) requestFactory).bufferRequestBody).isTrue();
-	}
-
 	@Test
 	void getOfUnconfigurableTypeWithConnectTimeoutThrows() {
 		assertThatIllegalStateException()
@@ -124,14 +116,6 @@ class ClientHttpRequestFactoriesTests {
 			.withMessageContaining("suitable setReadTimeout method");
 	}
 
-	@Test
-	void getOfUnconfigurableTypeWithBodyBufferingThrows() {
-		assertThatIllegalStateException()
-			.isThrownBy(() -> ClientHttpRequestFactories.get(UnconfigurableClientHttpRequestFactory.class,
-					ClientHttpRequestFactorySettings.DEFAULTS.withBufferRequestBody(true)))
-			.withMessageContaining("suitable setBufferRequestBody method");
-	}
-
 	@Test
 	void getOfTypeWithDeprecatedConnectTimeoutThrowsWithConnectTimeout() {
 		assertThatIllegalStateException()
@@ -148,14 +132,6 @@ class ClientHttpRequestFactoriesTests {
 			.withMessageContaining("setReadTimeout method marked as deprecated");
 	}
 
-	@Test
-	void getOfTypeWithDeprecatedBufferRequestBodyThrowsWithBufferRequestBody() {
-		assertThatIllegalStateException()
-			.isThrownBy(() -> ClientHttpRequestFactories.get(DeprecatedMethodsClientHttpRequestFactory.class,
-					ClientHttpRequestFactorySettings.DEFAULTS.withBufferRequestBody(false)))
-			.withMessageContaining("setBufferRequestBody method marked as deprecated");
-	}
-
 	@Test
 	void connectTimeoutCanBeConfiguredOnAWrappedRequestFactory() {
 		SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
@@ -176,25 +152,12 @@ class ClientHttpRequestFactoriesTests {
 		assertThat(requestFactory).hasFieldOrPropertyWithValue("readTimeout", 1234);
 	}
 
-	@Test
-	void bufferRequestBodyCanBeConfiguredOnAWrappedRequestFactory() {
-		SimpleClientHttpRequestFactory requestFactory = new SimpleClientHttpRequestFactory();
-		assertThat(requestFactory).hasFieldOrPropertyWithValue("bufferRequestBody", true);
-		BufferingClientHttpRequestFactory result = ClientHttpRequestFactories.get(
-				() -> new BufferingClientHttpRequestFactory(requestFactory),
-				ClientHttpRequestFactorySettings.DEFAULTS.withBufferRequestBody(false));
-		assertThat(result).extracting("requestFactory").isSameAs(requestFactory);
-		assertThat(requestFactory).hasFieldOrPropertyWithValue("bufferRequestBody", false);
-	}
-
 	public static class TestClientHttpRequestFactory implements ClientHttpRequestFactory {
 
 		private int connectTimeout;
 
 		private int readTimeout;
 
-		private boolean bufferRequestBody;
-
 		@Override
 		public ClientHttpRequest createRequest(URI uri, HttpMethod httpMethod) throws IOException {
 			throw new UnsupportedOperationException();
@@ -208,10 +171,6 @@ class ClientHttpRequestFactoriesTests {
 			this.readTimeout = timeout;
 		}
 
-		public void setBufferRequestBody(boolean bufferRequestBody) {
-			this.bufferRequestBody = bufferRequestBody;
-		}
-
 	}
 
 	public static class UnconfigurableClientHttpRequestFactory implements ClientHttpRequestFactory {

spring-boot-project/spring-boot/src/test/java/org/springframework/boot/web/client/ClientHttpRequestFactorySettingsTests.java

@@ -39,7 +39,6 @@ class ClientHttpRequestFactorySettingsTests {
 		ClientHttpRequestFactorySettings settings = ClientHttpRequestFactorySettings.DEFAULTS;
 		assertThat(settings.connectTimeout()).isNull();
 		assertThat(settings.readTimeout()).isNull();
-		assertThat(settings.bufferRequestBody()).isNull();
 		assertThat(settings.sslBundle()).isNull();
 	}
 
@@ -49,7 +48,6 @@ class ClientHttpRequestFactorySettingsTests {
 			.withConnectTimeout(ONE_SECOND);
 		assertThat(settings.connectTimeout()).isEqualTo(ONE_SECOND);
 		assertThat(settings.readTimeout()).isNull();
-		assertThat(settings.bufferRequestBody()).isNull();
 		assertThat(settings.sslBundle()).isNull();
 	}
 
@@ -59,17 +57,6 @@ class ClientHttpRequestFactorySettingsTests {
 			.withReadTimeout(ONE_SECOND);
 		assertThat(settings.connectTimeout()).isNull();
 		assertThat(settings.readTimeout()).isEqualTo(ONE_SECOND);
-		assertThat(settings.bufferRequestBody()).isNull();
-		assertThat(settings.sslBundle()).isNull();
-	}
-
-	@Test
-	void withBufferRequestBodyReturnsInstanceWithUpdatedBufferRequestBody() {
-		ClientHttpRequestFactorySettings settings = ClientHttpRequestFactorySettings.DEFAULTS
-			.withBufferRequestBody(true);
-		assertThat(settings.connectTimeout()).isNull();
-		assertThat(settings.readTimeout()).isNull();
-		assertThat(settings.bufferRequestBody()).isTrue();
 		assertThat(settings.sslBundle()).isNull();
 	}
 
@@ -79,7 +66,6 @@ class ClientHttpRequestFactorySettingsTests {
 		ClientHttpRequestFactorySettings settings = ClientHttpRequestFactorySettings.DEFAULTS.withSslBundle(sslBundle);
 		assertThat(settings.connectTimeout()).isNull();
 		assertThat(settings.readTimeout()).isNull();
-		assertThat(settings.bufferRequestBody()).isNull();
 		assertThat(settings.sslBundle()).isSameAs(sslBundle);
 	}
 

spring-boot-system-tests/spring-boot-image-tests/build.gradle

@@ -19,6 +19,11 @@ configurations {
 				if (dependency.requested.group.startsWith("com.fasterxml.jackson")) {
 					dependency.useVersion("2.14.2")
 				}
+				// Downgrade Spring Framework as Gradle cannot cope with 6.1.0-M1's
+				// multi-version jar files with bytecode in META-INF/versions/21
+				if (dependency.requested.group.equals("org.springframework")) {
+					dependency.useVersion("6.0.10")
+				}
 			}
 		}
 	}