Upgrade to Spring Boot 4.0.0-RC2 (#4774)

Upgrade Spring AI to Spring Boot 4.0.0-RC2 following the
https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-4.0-Migration-Guide

Major version upgrades:
- Spring Boot: 3.5.7 → 4.0.0-RC2
- Kotlin: 1.9.25 → 2.2.21 (with Kotlin compiler 2.2.21)
- Rest Assured: added BOM 5.5.6
- swagger-codegen-maven-plugin: 3.0.64 → 3.0.75
- Testcontainers: 1.20.4 → 2.0.1
  - Updated Elasticsearch test container to 9.2.0
  - Keep opensearch-testcontainers to 2.0.1 for Java 17 compatibility
  - Gemfire Testcontainers: 2.3.0 → 2.3.3

Spring Boot package reorganization:
- MongoDB: o.s.b.autoconfigure.mongo → o.s.b.mongodb.autoconfigure
- Data Redis: o.s.b.autoconfigure.data.redis → o.s.b.data.redis.autoconfigure
- JDBC: o.s.b.autoconfigure.jdbc → o.s.b.jdbc.autoconfigure
- Cassandra: o.s.b.autoconfigure.cassandra → o.s.b.cassandra.autoconfigure
- Neo4j: o.s.b.autoconfigure.neo4j → o.s.b.neo4j.autoconfigure
- Couchbase: o.s.b.autoconfigure.couchbase → o.s.b.couchbase.autoconfigure
- RestClient: o.s.b.autoconfigure.web.client → o.s.b.restclient.autoconfigure
- WebClient: o.s.b.autoconfigure.web.reactive → o.s.b.webclient.autoconfigure
- Servlet: o.s.b.autoconfigure.web.servlet → o.s.b.web.server.autoconfigure.servlet

Spring Framework 6.x/7.x compatibility:
- Add constructors without logic to *Api classes for better extensibility

Adopt new modular design of starters:
- Added explicit spring-boot-starter-* dependencies (jdbc, cassandra, mongodb, neo4j, elasticsearch, etc.)
- Added spring-boot-starter-restclient and spring-boot-starter-webclient where needed

Use new Jackson 3.x API:
- Updated import com.fasterxml.jackson.databind.json.JsonMapper
- Modified ObjectMapper configurations for compatibility

Migrated from Spring Retry to Spring Framework Retry:
- org.springframework.retry → org.springframework.core.retry
- Updated RetryTemplate, RetryPolicy, and RetryListener APIs
- Replaced RetryCallback/RetryContext with new Retryable interface

Property Mapper API changes:
- Updated PropertyMapper null handling (changed from .whenNonNull() to direct usage)
- Applied in Couchbase and Elasticsearch vector store configurations

API changes:
- Replaced MultiValueMap<String, String> with HttpHeaders for HTTP headers
- Updated Elasticsearch client to use Rest5Client (from RestClient)
- Standardized header handling across OpenAI, Anthropic, DeepSeek, MiniMax, ZhiPuAI, Mistral AI, and other APIs
- Added overloaded constructors accepting RestClient/WebClient directly
- Updated HttpHeaders methods (.containsKey() → .get())

Testcontainers artifact naming:
- Standardized to prefixed format (e.g., junit-jupiter → testcontainers-junit-jupiter)
- Updated across all modules: Cassandra, PostgreSQL, MongoDB, Neo4j, Milvus, Qdrant, etc.

Additional improvements:
- Updated Swagger codegen templates for Huggingface model to align with latest Spring Framework APIs
- Added FailureDetectingExternalResource from old testcontainers versions for gemfire-testcontainers compatibility
- Updated Kotlin nullable type handling in extensions (reified T → reified T : Any)
- Added missing test dependencies (spring-boot-restclient-test, spring-boot-starter-jdbc-test)

Resolves: #3379

Extends and replaces: #4771, #4681

Co-authored-by: Paul Bakker <[email protected]>

Signed-off-by: Dmitry Bedrin <[email protected]>
Signed-off-by: Christian Tzolov <[email protected]>

Author: bedrin

README.md

@@ -1,5 +1,11 @@
 # Spring AI [![build status](https://github.com/spring-projects/spring-ai/actions/workflows/continuous-integration.yml/badge.svg)](https://github.com/spring-projects/spring-ai/actions/workflows/continuous-integration.yml) [![build status](https://github.com/spring-projects/spring-ai-integration-tests/actions/workflows/spring-ai-integration-tests.yml/badge.svg)](https://github.com/spring-projects/spring-ai-integration-tests/actions/workflows/spring-ai-integration-tests.yml)
 
+### Spring Boot Version Compatibility
+
+> **Spring AI 2.x.x** ([main](https://github.com/spring-projects/spring-ai/tree/main) branch) - Spring Boot `4.x`
+>
+> **Spring AI 1.1.x** ([1.1.x](https://github.com/spring-projects/spring-ai/tree/1.1.x) branch) - Spring Boot `3.5.x`
+
 
 The Spring AI project provides a Spring-friendly API and abstractions for developing AI applications.
 

auto-configurations/common/spring-ai-autoconfigure-retry/pom.xml

@@ -61,6 +61,11 @@
 			<artifactId>spring-boot-starter-test</artifactId>
 			<scope>test</scope>
 		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-restclient-test</artifactId>
+			<scope>test</scope>
+		</dependency>
 
 		<dependency>
 			<groupId>org.mockito</groupId>

auto-configurations/common/spring-ai-autoconfigure-retry/src/main/java/org/springframework/ai/retry/autoconfigure/SpringAiRetryAutoConfiguration.java

@@ -17,7 +17,9 @@
 package org.springframework.ai.retry.autoconfigure;
 
 import java.io.IOException;
+import java.net.URI;
 import java.nio.charset.StandardCharsets;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -30,16 +32,15 @@
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.context.properties.EnableConfigurationProperties;
 import org.springframework.context.annotation.Bean;
+import org.springframework.core.retry.RetryListener;
+import org.springframework.core.retry.RetryPolicy;
+import org.springframework.core.retry.RetryTemplate;
+import org.springframework.core.retry.Retryable;
+import org.springframework.http.HttpMethod;
 import org.springframework.http.client.ClientHttpResponse;
 import org.springframework.lang.NonNull;
-import org.springframework.retry.RetryCallback;
-import org.springframework.retry.RetryContext;
-import org.springframework.retry.RetryListener;
-import org.springframework.retry.support.RetryTemplate;
-import org.springframework.retry.support.RetryTemplateBuilder;
 import org.springframework.util.CollectionUtils;
 import org.springframework.util.StreamUtils;
-import org.springframework.web.client.ResourceAccessException;
 import org.springframework.web.client.ResponseErrorHandler;
 
 /**
@@ -61,35 +62,25 @@ public class SpringAiRetryAutoConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	public RetryTemplate retryTemplate(SpringAiRetryProperties properties) {
-		RetryTemplateBuilder builder = RetryTemplate.builder()
+		RetryPolicy retryPolicy = RetryPolicy.builder()
 			.maxAttempts(properties.getMaxAttempts())
-			.retryOn(TransientAiException.class)
-			.retryOn(ResourceAccessException.class)
-			.exponentialBackoff(properties.getBackoff().getInitialInterval(), properties.getBackoff().getMultiplier(),
-					properties.getBackoff().getMaxInterval())
-			.withListener(new RetryListener() {
-
-				@Override
-				public <T, E extends Throwable> void onError(RetryContext context, RetryCallback<T, E> callback,
-						Throwable throwable) {
-					logger.warn("Retry error. Retry count: {}, Exception: {}", context.getRetryCount(),
-							throwable.getMessage(), throwable);
-				}
-			});
-
-		// Optionally add WebFlux pre-response network errors if present
-		try {
-			Class<?> webClientRequestEx = Class
-				.forName("org.springframework.web.reactive.function.client.WebClientRequestException");
-			@SuppressWarnings("unchecked")
-			Class<? extends Throwable> exClass = (Class<? extends Throwable>) webClientRequestEx;
-			builder.retryOn(exClass);
-		}
-		catch (ClassNotFoundException ignore) {
-			// WebFlux not on classpath; skip
-		}
-
-		return builder.build();
+			.includes(TransientAiException.class)
+			.delay(properties.getBackoff().getInitialInterval())
+			.multiplier(properties.getBackoff().getMultiplier())
+			.maxDelay(properties.getBackoff().getMaxInterval())
+			.build();
+
+		RetryTemplate retryTemplate = new RetryTemplate(retryPolicy);
+		retryTemplate.setRetryListener(new RetryListener() {
+			private final AtomicInteger retryCount = new AtomicInteger(0);
+
+			@Override
+			public void onRetryFailure(RetryPolicy policy, Retryable<?> retryable, Throwable throwable) {
+				int currentRetries = this.retryCount.incrementAndGet();
+				logger.warn("Retry error. Retry count:{}", currentRetries, throwable);
+			}
+		});
+		return retryTemplate;
 	}
 
 	@Bean
@@ -104,6 +95,12 @@ public boolean hasError(@NonNull ClientHttpResponse response) throws IOException
 			}
 
 			@Override
+			public void handleError(@NonNull URI url, @NonNull HttpMethod method, @NonNull ClientHttpResponse response)
+					throws IOException {
+				handleError(response);
+			}
+
+			@SuppressWarnings("removal")
 			public void handleError(@NonNull ClientHttpResponse response) throws IOException {
 				if (!response.getStatusCode().isError()) {
 					return;

auto-configurations/common/spring-ai-autoconfigure-retry/src/test/java/org/springframework/ai/retry/autoconfigure/SpringAiRetryAutoConfigurationIT.java

@@ -19,9 +19,9 @@
 import org.junit.jupiter.api.Test;
 
 import org.springframework.boot.autoconfigure.AutoConfigurations;
-import org.springframework.boot.autoconfigure.web.client.RestClientAutoConfiguration;
+import org.springframework.boot.restclient.autoconfigure.RestClientAutoConfiguration;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
-import org.springframework.retry.support.RetryTemplate;
+import org.springframework.core.retry.RetryTemplate;
 import org.springframework.web.client.ResponseErrorHandler;
 
 import static org.assertj.core.api.Assertions.assertThat;

auto-configurations/mcp/spring-ai-autoconfigure-mcp-client-httpclient/pom.xml

@@ -82,7 +82,7 @@
 
 		<dependency>
 			<groupId>org.testcontainers</groupId>
-			<artifactId>junit-jupiter</artifactId>
+			<artifactId>testcontainers-junit-jupiter</artifactId>
 			<scope>test</scope>
 		</dependency>
 	</dependencies>

auto-configurations/mcp/spring-ai-autoconfigure-mcp-client-webflux/pom.xml

@@ -88,7 +88,7 @@
 
 		<dependency>
 			<groupId>org.testcontainers</groupId>
-			<artifactId>junit-jupiter</artifactId>
+			<artifactId>testcontainers-junit-jupiter</artifactId>
 			<scope>test</scope>
 		</dependency>
 

auto-configurations/mcp/spring-ai-autoconfigure-mcp-server-webflux/pom.xml

@@ -95,6 +95,17 @@
 			<scope>test</scope>
 		</dependency>
 
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-restclient</artifactId>
+			<scope>test</scope>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-webclient</artifactId>
+			<scope>test</scope>
+		</dependency>
+
 		<dependency>
 			<groupId>org.springframework.ai</groupId>
 			<artifactId>spring-ai-autoconfigure-model-anthropic</artifactId>

auto-configurations/mcp/spring-ai-autoconfigure-mcp-server-webflux/src/test/java/org/springframework/ai/mcp/server/autoconfigure/McpServerSseWebFluxAutoConfigurationTests.java

@@ -16,7 +16,7 @@
 
 package org.springframework.ai.mcp.server.autoconfigure;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
+import com.fasterxml.jackson.databind.json.JsonMapper;
 import io.modelcontextprotocol.server.transport.WebFluxSseServerTransportProvider;
 import org.junit.jupiter.api.Test;
 
@@ -43,10 +43,11 @@ void shouldConfigureWebFluxTransportWithCustomObjectMapper() {
 			assertThat(context).hasSingleBean(RouterFunction.class);
 			assertThat(context).hasSingleBean(McpServerProperties.class);
 
-			ObjectMapper objectMapper = context.getBean("mcpServerObjectMapper", ObjectMapper.class);
+			JsonMapper jsonMapper = context.getBean("mcpServerObjectMapper", JsonMapper.class);
 
-			// Verify that the ObjectMapper is configured to ignore unknown properties
-			assertThat(objectMapper.getDeserializationConfig()
+			// Verify that the JsonMapper is configured to ignore unknown properties
+
+			assertThat(jsonMapper
 				.isEnabled(com.fasterxml.jackson.databind.DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES)).isFalse();
 
 			// Test with a JSON payload containing unknown fields
@@ -61,7 +62,7 @@ void shouldConfigureWebFluxTransportWithCustomObjectMapper() {
 			// CHECKSTYLE:ON
 
 			// This should not throw an exception
-			TestMessage message = objectMapper.readValue(jsonWithUnknownField, TestMessage.class);
+			TestMessage message = jsonMapper.readValue(jsonWithUnknownField, TestMessage.class);
 			assertThat(message.getName()).isEqualTo("test");
 		});
 	}

auto-configurations/mcp/spring-ai-autoconfigure-mcp-server-webflux/src/test/java/org/springframework/ai/mcp/server/autoconfigure/McpToolCallProviderCachingIT.java

@@ -48,9 +48,9 @@
 import org.springframework.ai.tool.ToolCallbackProvider;
 import org.springframework.ai.tool.function.FunctionToolCallback;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
-import org.springframework.boot.autoconfigure.web.client.RestClientAutoConfiguration;
-import org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration;
+import org.springframework.boot.restclient.autoconfigure.RestClientAutoConfiguration;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.boot.webclient.autoconfigure.WebClientAutoConfiguration;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.http.server.reactive.HttpHandler;

auto-configurations/mcp/spring-ai-autoconfigure-mcp-server-webflux/src/test/java/org/springframework/ai/mcp/server/autoconfigure/McpToolCallbackParameterlessToolIT.java

@@ -48,9 +48,9 @@
 import org.springframework.ai.tool.ToolCallbackProvider;
 import org.springframework.ai.tool.definition.ToolDefinition;
 import org.springframework.boot.autoconfigure.AutoConfigurations;
-import org.springframework.boot.autoconfigure.web.client.RestClientAutoConfiguration;
-import org.springframework.boot.autoconfigure.web.reactive.function.client.WebClientAutoConfiguration;
+import org.springframework.boot.restclient.autoconfigure.RestClientAutoConfiguration;
 import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.boot.webclient.autoconfigure.WebClientAutoConfiguration;
 import org.springframework.context.ApplicationContext;
 import org.springframework.http.server.reactive.HttpHandler;
 import org.springframework.http.server.reactive.ReactorHttpHandlerAdapter;