Add nullability annotations to module/spring-boot-restclient

See gh-46587

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/BasicAuthentication.java

@@ -18,6 +18,8 @@ package org.springframework.boot.restclient;
 
 import java.nio.charset.Charset;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.http.HttpHeaders;
 import org.springframework.util.Assert;
 
@@ -33,9 +35,9 @@ class BasicAuthentication {
 
 	private final String password;
 
-	private final Charset charset;
+	private final @Nullable Charset charset;
 
-	BasicAuthentication(String username, String password, Charset charset) {
+	BasicAuthentication(String username, String password, @Nullable Charset charset) {
 		Assert.notNull(username, "'username' must not be null");
 		Assert.notNull(password, "'password' must not be null");
 		this.username = username;

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/RestTemplateBuilder.java

@@ -30,6 +30,8 @@ import java.util.Set;
 import java.util.function.Supplier;
 import java.util.function.UnaryOperator;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.BeanUtils;
 import org.springframework.boot.http.client.ClientHttpRequestFactoryBuilder;
 import org.springframework.boot.http.client.ClientHttpRequestFactorySettings;
@@ -74,19 +76,19 @@ public class RestTemplateBuilder {
 
 	private final boolean detectRequestFactory;
 
-	private final String rootUri;
+	private final @Nullable String rootUri;
 
-	private final Set<HttpMessageConverter<?>> messageConverters;
+	private final @Nullable Set<HttpMessageConverter<?>> messageConverters;
 
 	private final Set<ClientHttpRequestInterceptor> interceptors;
 
-	private final ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder;
+	private final @Nullable ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder;
 
-	private final UriTemplateHandler uriTemplateHandler;
+	private final @Nullable UriTemplateHandler uriTemplateHandler;
 
-	private final ResponseErrorHandler errorHandler;
+	private final @Nullable ResponseErrorHandler errorHandler;
 
-	private final BasicAuthentication basicAuthentication;
+	private final @Nullable BasicAuthentication basicAuthentication;
 
 	private final Map<String, List<String>> defaultHeaders;
 
@@ -116,10 +118,11 @@ public class RestTemplateBuilder {
 	}
 
 	private RestTemplateBuilder(ClientHttpRequestFactorySettings requestFactorySettings, boolean detectRequestFactory,
-			String rootUri, Set<HttpMessageConverter<?>> messageConverters,
-			Set<ClientHttpRequestInterceptor> interceptors, ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder,
-			UriTemplateHandler uriTemplateHandler, ResponseErrorHandler errorHandler,
-			BasicAuthentication basicAuthentication, Map<String, List<String>> defaultHeaders,
+			@Nullable String rootUri, @Nullable Set<HttpMessageConverter<?>> messageConverters,
+			Set<ClientHttpRequestInterceptor> interceptors,
+			@Nullable ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder,
+			@Nullable UriTemplateHandler uriTemplateHandler, @Nullable ResponseErrorHandler errorHandler,
+			@Nullable BasicAuthentication basicAuthentication, Map<String, List<String>> defaultHeaders,
 			Set<RestTemplateCustomizer> customizers, Set<RestTemplateRequestCustomizer<?>> requestCustomizers) {
 		this.requestFactorySettings = requestFactorySettings;
 		this.detectRequestFactory = detectRequestFactory;
@@ -156,7 +159,7 @@ public class RestTemplateBuilder {
 	 * @param rootUri the root URI or {@code null}
 	 * @return a new builder instance
 	 */
-	public RestTemplateBuilder rootUri(String rootUri) {
+	public RestTemplateBuilder rootUri(@Nullable String rootUri) {
 		return new RestTemplateBuilder(this.requestFactorySettings, this.detectRequestFactory, rootUri,
 				this.messageConverters, this.interceptors, this.requestFactoryBuilder, this.uriTemplateHandler,
 				this.errorHandler, this.basicAuthentication, this.defaultHeaders, this.customizers,
@@ -390,7 +393,7 @@ public class RestTemplateBuilder {
 	 * @return a new builder instance
 	 * @since 2.2.0
 	 */
-	public RestTemplateBuilder basicAuthentication(String username, String password, Charset charset) {
+	public RestTemplateBuilder basicAuthentication(String username, String password, @Nullable Charset charset) {
 		return new RestTemplateBuilder(this.requestFactorySettings, this.detectRequestFactory, this.rootUri,
 				this.messageConverters, this.interceptors, this.requestFactoryBuilder, this.uriTemplateHandler,
 				this.errorHandler, new BasicAuthentication(username, password, charset), this.defaultHeaders,
@@ -688,7 +691,7 @@ public class RestTemplateBuilder {
 	 * @return a {@link ClientHttpRequestFactory} or {@code null}
 	 * @since 2.2.0
 	 */
-	public ClientHttpRequestFactory buildRequestFactory() {
+	public @Nullable ClientHttpRequestFactory buildRequestFactory() {
 		ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder = requestFactoryBuilder();
 		return (requestFactoryBuilder != null) ? requestFactoryBuilder.build(this.requestFactorySettings) : null;
 	}
@@ -699,7 +702,7 @@ public class RestTemplateBuilder {
 	 * @return a {@link ClientHttpRequestFactoryBuilder} or {@code null}
 	 * @since 3.5.0
 	 */
-	public ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder() {
+	public @Nullable ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder() {
 		if (this.requestFactoryBuilder != null) {
 			return this.requestFactoryBuilder;
 		}
@@ -731,7 +734,8 @@ public class RestTemplateBuilder {
 		return Collections.unmodifiableList(Arrays.asList(Arrays.copyOf(items, items.length)));
 	}
 
-	private static <T> Set<T> append(Collection<? extends T> collection, Collection<? extends T> additions) {
+	private static <T> Set<T> append(@Nullable Collection<? extends T> collection,
+			@Nullable Collection<? extends T> additions) {
 		Set<T> result = new LinkedHashSet<>((collection != null) ? collection : Collections.emptySet());
 		if (additions != null) {
 			result.addAll(additions);
@@ -739,7 +743,7 @@ public class RestTemplateBuilder {
 		return Collections.unmodifiableSet(result);
 	}
 
-	private static <K, V> Map<K, List<V>> append(Map<K, List<V>> map, K key, V[] values) {
+	private static <K, V> Map<K, List<V>> append(@Nullable Map<K, List<V>> map, K key, V @Nullable [] values) {
 		Map<K, List<V>> result = new LinkedHashMap<>((map != null) ? map : Collections.emptyMap());
 		if (values != null) {
 			result.put(key, copiedListOf(values));

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/RestTemplateBuilderClientHttpRequestInitializer.java

@@ -20,6 +20,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.util.LambdaSafe;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.client.ClientHttpRequest;
@@ -34,13 +36,13 @@ import org.springframework.http.client.ClientHttpRequestInitializer;
  */
 class RestTemplateBuilderClientHttpRequestInitializer implements ClientHttpRequestInitializer {
 
-	private final BasicAuthentication basicAuthentication;
+	private final @Nullable BasicAuthentication basicAuthentication;
 
 	private final Map<String, List<String>> defaultHeaders;
 
 	private final Set<RestTemplateRequestCustomizer<?>> requestCustomizers;
 
-	RestTemplateBuilderClientHttpRequestInitializer(BasicAuthentication basicAuthentication,
+	RestTemplateBuilderClientHttpRequestInitializer(@Nullable BasicAuthentication basicAuthentication,
 			Map<String, List<String>> defaultHeaders, Set<RestTemplateRequestCustomizer<?>> requestCustomizers) {
 		this.basicAuthentication = basicAuthentication;
 		this.defaultHeaders = defaultHeaders;

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/RootUriTemplateHandler.java

@@ -19,6 +19,8 @@ package org.springframework.boot.restclient;
 import java.net.URI;
 import java.util.Map;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.util.Assert;
 import org.springframework.util.StringUtils;
 import org.springframework.web.util.UriTemplateHandler;
@@ -32,7 +34,7 @@ import org.springframework.web.util.UriTemplateHandler;
  */
 public class RootUriTemplateHandler implements UriTemplateHandler {
 
-	private final String rootUri;
+	private final @Nullable String rootUri;
 
 	private final UriTemplateHandler handler;
 
@@ -55,7 +57,7 @@ public class RootUriTemplateHandler implements UriTemplateHandler {
 	}
 
 	@Override
-	public URI expand(String uriTemplate, Object... uriVariables) {
+	public URI expand(String uriTemplate, @Nullable Object... uriVariables) {
 		return this.handler.expand(apply(uriTemplate), uriVariables);
 	}
 
@@ -66,7 +68,7 @@ public class RootUriTemplateHandler implements UriTemplateHandler {
 		return uriTemplate;
 	}
 
-	public String getRootUri() {
+	public @Nullable String getRootUri() {
 		return this.rootUri;
 	}
 

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/AbstractRestClientProperties.java

@@ -20,6 +20,8 @@ import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.context.properties.NestedConfigurationProperty;
 import org.springframework.boot.http.client.autoconfigure.AbstractHttpRequestFactoryProperties;
 import org.springframework.boot.http.client.autoconfigure.ApiversionProperties;
@@ -40,7 +42,7 @@ public abstract class AbstractRestClientProperties extends AbstractHttpRequestFa
 	 * Base url to set in the underlying HTTP client group. By default, set to
 	 * {@code null}.
 	 */
-	private String baseUrl;
+	private @Nullable String baseUrl;
 
 	/**
 	 * Default request headers for interface client group. By default, set to empty
@@ -54,11 +56,11 @@ public abstract class AbstractRestClientProperties extends AbstractHttpRequestFa
 	@NestedConfigurationProperty
 	private final ApiversionProperties apiversion = new ApiversionProperties();
 
-	public String getBaseUrl() {
+	public @Nullable String getBaseUrl() {
 		return this.baseUrl;
 	}
 
-	public void setBaseUrl(String baseUrl) {
+	public void setBaseUrl(@Nullable String baseUrl) {
 		this.baseUrl = baseUrl;
 	}
 

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/HttpMessageConvertersRestClientCustomizer.java

@@ -19,6 +19,8 @@ package org.springframework.boot.restclient.autoconfigure;
 import java.util.Arrays;
 import java.util.List;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.http.converter.autoconfigure.HttpMessageConverters;
 import org.springframework.boot.restclient.RestClientCustomizer;
 import org.springframework.http.converter.HttpMessageConverter;
@@ -34,14 +36,14 @@ import org.springframework.web.client.RestClient;
  */
 public class HttpMessageConvertersRestClientCustomizer implements RestClientCustomizer {
 
-	private final Iterable<? extends HttpMessageConverter<?>> messageConverters;
+	private final @Nullable Iterable<? extends HttpMessageConverter<?>> messageConverters;
 
 	public HttpMessageConvertersRestClientCustomizer(HttpMessageConverter<?>... messageConverters) {
 		Assert.notNull(messageConverters, "'messageConverters' must not be null");
 		this.messageConverters = Arrays.asList(messageConverters);
 	}
 
-	HttpMessageConvertersRestClientCustomizer(HttpMessageConverters messageConverters) {
+	HttpMessageConvertersRestClientCustomizer(@Nullable HttpMessageConverters messageConverters) {
 		this.messageConverters = messageConverters;
 	}
 

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/PropertiesRestClientCustomizer.java

@@ -21,6 +21,8 @@ import java.util.List;
 import java.util.Map;
 import java.util.function.Consumer;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.context.properties.PropertyMapper;
 import org.springframework.boot.http.client.autoconfigure.ApiversionProperties;
 import org.springframework.boot.http.client.autoconfigure.PropertiesApiVersionInserter;
@@ -29,6 +31,7 @@ import org.springframework.http.HttpHeaders;
 import org.springframework.web.client.ApiVersionFormatter;
 import org.springframework.web.client.ApiVersionInserter;
 import org.springframework.web.client.RestClient;
+import org.springframework.web.client.RestClient.Builder;
 
 /**
  * {@link RestClientCustomizer} to apply {@link AbstractRestClientProperties}.
@@ -38,18 +41,19 @@ import org.springframework.web.client.RestClient;
  */
 public class PropertiesRestClientCustomizer implements RestClientCustomizer {
 
-	private final AbstractRestClientProperties[] orderedProperties;
+	private final @Nullable AbstractRestClientProperties[] orderedProperties;
 
-	private ApiVersionInserter apiVersionInserter;
+	private final @Nullable ApiVersionInserter apiVersionInserter;
 
-	public PropertiesRestClientCustomizer(ApiVersionInserter apiVersionInserter,
-			ApiVersionFormatter apiVersionFormatter, AbstractRestClientProperties... orderedProperties) {
+	public PropertiesRestClientCustomizer(@Nullable ApiVersionInserter apiVersionInserter,
+			@Nullable ApiVersionFormatter apiVersionFormatter,
+			@Nullable AbstractRestClientProperties... orderedProperties) {
 		this.orderedProperties = orderedProperties;
 		this.apiVersionInserter = PropertiesApiVersionInserter.get(apiVersionInserter, apiVersionFormatter,
 				Arrays.stream(orderedProperties).map(this::getApiVersion));
 	}
 
-	private ApiversionProperties getApiVersion(AbstractRestClientProperties properties) {
+	private @Nullable ApiversionProperties getApiVersion(@Nullable AbstractRestClientProperties properties) {
 		return (properties != null) ? properties.getApiversion() : null;
 	}
 
@@ -62,13 +66,16 @@ public class PropertiesRestClientCustomizer implements RestClientCustomizer {
 			if (properties != null) {
 				map.from(properties::getBaseUrl).whenHasText().to(builder::baseUrl);
 				map.from(properties::getDefaultHeader).as(this::putAllHeaders).to(builder::defaultHeaders);
-				map.from(properties.getApiversion())
-					.as(ApiversionProperties::getDefaultVersion)
-					.to(builder::defaultApiVersion);
+				setDefaultApiVersion(builder, map, properties);
 			}
 		}
 	}
 
+	@SuppressWarnings("NullAway") // Lambda isn't detected with the correct nullability
+	private void setDefaultApiVersion(Builder builder, PropertyMapper map, AbstractRestClientProperties properties) {
+		map.from(properties.getApiversion()).as(ApiversionProperties::getDefaultVersion).to(builder::defaultApiVersion);
+	}
+
 	private Consumer<HttpHeaders> putAllHeaders(Map<String, List<String>> defaultHeaders) {
 		return (httpHeaders) -> httpHeaders.putAll(defaultHeaders);
 	}

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/RestClientBuilderConfigurer.java

@@ -19,6 +19,8 @@ package org.springframework.boot.restclient.autoconfigure;
 import java.util.Collections;
 import java.util.List;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.http.client.ClientHttpRequestFactoryBuilder;
 import org.springframework.boot.http.client.ClientHttpRequestFactorySettings;
 import org.springframework.boot.restclient.RestClientCustomizer;
@@ -43,7 +45,7 @@ public class RestClientBuilderConfigurer {
 
 	private final List<RestClientCustomizer> customizers;
 
-	private final PropertiesRestClientCustomizer propertiesCustomizer;
+	private final @Nullable PropertiesRestClientCustomizer propertiesCustomizer;
 
 	public RestClientBuilderConfigurer() {
 		this(ClientHttpRequestFactoryBuilder.detect(), ClientHttpRequestFactorySettings.defaults(), null,
@@ -52,7 +54,7 @@ public class RestClientBuilderConfigurer {
 
 	RestClientBuilderConfigurer(ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder,
 			ClientHttpRequestFactorySettings requestFactorySettings,
-			PropertiesRestClientCustomizer propertiesCustomizer, List<RestClientCustomizer> customizers) {
+			@Nullable PropertiesRestClientCustomizer propertiesCustomizer, List<RestClientCustomizer> customizers) {
 		this.requestFactoryBuilder = requestFactoryBuilder;
 		this.requestFactorySettings = requestFactorySettings;
 		this.propertiesCustomizer = propertiesCustomizer;

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/RestTemplateBuilderConfigurer.java

@@ -20,6 +20,8 @@ import java.util.Collection;
 import java.util.List;
 import java.util.function.BiFunction;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.boot.http.client.ClientHttpRequestFactoryBuilder;
 import org.springframework.boot.http.client.ClientHttpRequestFactorySettings;
 import org.springframework.boot.http.converter.autoconfigure.HttpMessageConverters;
@@ -40,33 +42,34 @@ import org.springframework.util.ObjectUtils;
  */
 public final class RestTemplateBuilderConfigurer {
 
-	private ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder;
+	private @Nullable ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder;
 
-	private ClientHttpRequestFactorySettings requestFactorySettings;
+	private @Nullable ClientHttpRequestFactorySettings requestFactorySettings;
 
-	private HttpMessageConverters httpMessageConverters;
+	private @Nullable HttpMessageConverters httpMessageConverters;
 
-	private List<RestTemplateCustomizer> restTemplateCustomizers;
+	private @Nullable List<RestTemplateCustomizer> restTemplateCustomizers;
 
-	private List<RestTemplateRequestCustomizer<?>> restTemplateRequestCustomizers;
+	private @Nullable List<RestTemplateRequestCustomizer<?>> restTemplateRequestCustomizers;
 
-	void setRequestFactoryBuilder(ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder) {
+	void setRequestFactoryBuilder(@Nullable ClientHttpRequestFactoryBuilder<?> requestFactoryBuilder) {
 		this.requestFactoryBuilder = requestFactoryBuilder;
 	}
 
-	void setRequestFactorySettings(ClientHttpRequestFactorySettings requestFactorySettings) {
+	void setRequestFactorySettings(@Nullable ClientHttpRequestFactorySettings requestFactorySettings) {
 		this.requestFactorySettings = requestFactorySettings;
 	}
 
-	void setHttpMessageConverters(HttpMessageConverters httpMessageConverters) {
+	void setHttpMessageConverters(@Nullable HttpMessageConverters httpMessageConverters) {
 		this.httpMessageConverters = httpMessageConverters;
 	}
 
-	void setRestTemplateCustomizers(List<RestTemplateCustomizer> restTemplateCustomizers) {
+	void setRestTemplateCustomizers(@Nullable List<RestTemplateCustomizer> restTemplateCustomizers) {
 		this.restTemplateCustomizers = restTemplateCustomizers;
 	}
 
-	void setRestTemplateRequestCustomizers(List<RestTemplateRequestCustomizer<?>> restTemplateRequestCustomizers) {
+	void setRestTemplateRequestCustomizers(
+			@Nullable List<RestTemplateRequestCustomizer<?>> restTemplateRequestCustomizers) {
 		this.restTemplateRequestCustomizers = restTemplateRequestCustomizers;
 	}
 
@@ -91,7 +94,7 @@ public final class RestTemplateBuilderConfigurer {
 		return builder;
 	}
 
-	private <T> RestTemplateBuilder addCustomizers(RestTemplateBuilder builder, List<T> customizers,
+	private <T> RestTemplateBuilder addCustomizers(RestTemplateBuilder builder, @Nullable List<T> customizers,
 			BiFunction<RestTemplateBuilder, Collection<T>, RestTemplateBuilder> method) {
 		if (!ObjectUtils.isEmpty(customizers)) {
 			return method.apply(builder, customizers);

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/package-info.java

@@ -17,4 +17,7 @@
 /**
  * Auto-configuration for RestClient and RestTemplate.
  */
+@NullMarked
 package org.springframework.boot.restclient.autoconfigure;
+
+import org.jspecify.annotations.NullMarked;

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/service/HttpServiceClientAutoConfiguration.java

@@ -55,6 +55,7 @@ import org.springframework.web.service.registry.ImportHttpServices;
 @EnableConfigurationProperties(HttpClientServiceProperties.class)
 public final class HttpServiceClientAutoConfiguration implements BeanClassLoaderAware {
 
+	@SuppressWarnings("NullAway.Init")
 	private ClassLoader beanClassLoader;
 
 	HttpServiceClientAutoConfiguration() {

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/service/RestClientPropertiesHttpServiceGroupConfigurer.java

@@ -16,6 +16,8 @@
 
 package org.springframework.boot.restclient.autoconfigure.service;
 
+import org.jspecify.annotations.Nullable;
+
 import org.springframework.beans.factory.ObjectProvider;
 import org.springframework.boot.http.client.ClientHttpRequestFactoryBuilder;
 import org.springframework.boot.http.client.ClientHttpRequestFactorySettings;
@@ -44,7 +46,7 @@ class RestClientPropertiesHttpServiceGroupConfigurer implements RestClientHttpSe
 
 	private final ObjectProvider<SslBundles> sslBundles;
 
-	private final HttpClientProperties clientProperties;
+	private final @Nullable HttpClientProperties clientProperties;
 
 	private final HttpClientServiceProperties serviceProperties;
 
@@ -52,12 +54,12 @@ class RestClientPropertiesHttpServiceGroupConfigurer implements RestClientHttpSe
 
 	private final ObjectProvider<ClientHttpRequestFactorySettings> requestFactorySettings;
 
-	private final ApiVersionInserter apiVersionInserter;
+	private final @Nullable ApiVersionInserter apiVersionInserter;
 
-	private final ApiVersionFormatter apiVersionFormatter;
+	private final @Nullable ApiVersionFormatter apiVersionFormatter;
 
 	RestClientPropertiesHttpServiceGroupConfigurer(ClassLoader classLoader, ObjectProvider<SslBundles> sslBundles,
-			HttpClientProperties clientProperties, HttpClientServiceProperties serviceProperties,
+			@Nullable HttpClientProperties clientProperties, HttpClientServiceProperties serviceProperties,
 			ObjectProvider<ClientHttpRequestFactoryBuilder<?>> requestFactoryBuilder,
 			ObjectProvider<ClientHttpRequestFactorySettings> requestFactorySettings,
 			ObjectProvider<ApiVersionInserter> apiVersionInserter,
@@ -89,12 +91,12 @@ class RestClientPropertiesHttpServiceGroupConfigurer implements RestClientHttpSe
 	}
 
 	private PropertiesRestClientCustomizer getPropertiesRestClientCustomizer(
-			HttpClientServiceProperties.Group groupProperties) {
+			HttpClientServiceProperties.@Nullable Group groupProperties) {
 		return new PropertiesRestClientCustomizer(this.apiVersionInserter, this.apiVersionFormatter, groupProperties,
 				this.serviceProperties);
 	}
 
-	private ClientHttpRequestFactory getRequestFactory(HttpClientServiceProperties.Group groupProperties) {
+	private ClientHttpRequestFactory getRequestFactory(HttpClientServiceProperties.@Nullable Group groupProperties) {
 		ClientHttpRequestFactories factories = new ClientHttpRequestFactories(this.sslBundles, groupProperties,
 				this.serviceProperties, this.clientProperties);
 		ClientHttpRequestFactoryBuilder<?> builder = this.requestFactoryBuilder

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/autoconfigure/service/package-info.java

@@ -17,4 +17,7 @@
 /**
  * Auto-Configuration for Spring's Blocking HTTP Service Interface Clients.
  */
+@NullMarked
 package org.springframework.boot.restclient.autoconfigure.service;
+
+import org.jspecify.annotations.NullMarked;

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/observation/package-info.java

@@ -17,4 +17,7 @@
 /**
  * Observation integration for RestClient and RestTemplate.
  */
+@NullMarked
 package org.springframework.boot.restclient.observation;
+
+import org.jspecify.annotations.NullMarked;

module/spring-boot-restclient/src/main/java/org/springframework/boot/restclient/package-info.java

@@ -17,4 +17,7 @@
 /**
  * Web client utilities.
  */
+@NullMarked
 package org.springframework.boot.restclient;
+
+import org.jspecify.annotations.NullMarked;