feat: upgrade to Spring Boot 4.0 and JDK 25 LTS

.github/copilot-instructions.md

@@ -2,7 +2,7 @@
 
 ## Project Overview
 
-This is a RESTful Web Service proof-of-concept built with **Spring Boot 3** targeting **JDK 21 (LTS)**. The application demonstrates a clean, layered architecture implementing a CRUD API for managing books. It uses an in-memory H2 database for data persistence and includes comprehensive test coverage.
+This is a RESTful Web Service proof-of-concept built with **Spring Boot 4** targeting **JDK 25 (LTS)**. The application demonstrates a clean, layered architecture implementing a CRUD API for managing books. It uses an in-memory H2 database for data persistence and includes comprehensive test coverage.
 
 **Key URLs:**
 
@@ -14,8 +14,8 @@ This is a RESTful Web Service proof-of-concept built with **Spring Boot 3** targ
 
 ### Core Framework & Runtime
 
-- **Java**: JDK 21 (LTS) - use modern Java features where appropriate
-- **Spring Boot**: 3.4.4 with starter dependencies (Web, Data JPA, Validation, Cache, Actuator)
+- **Java**: JDK 25 (LTS) - use modern Java features where appropriate
+- **Spring Boot**: 4.0.0 with modular starter dependencies (WebMVC, Data JPA, Validation, Cache, Actuator)
 - **Build Tool**: Maven 3.9+ (use `./mvnw` wrapper, NOT system Maven)
 - **Database**: H2 in-memory database (runtime scope)
 
@@ -31,15 +31,14 @@ This is a RESTful Web Service proof-of-concept built with **Spring Boot 3** targ
 
 - **JUnit 5** (Jupiter): Test framework
 - **Mockito**: Mocking framework
-- **Spring Boot Test**: `@WebMvcTest`, `@DataJpaTest`, etc.
+- **Spring Boot Test**: `@WebMvcTest`, `@DataJpaTest`, `@AutoConfigureCache`, etc.
 - **AssertJ**: Preferred assertion library (use over standard JUnit assertions)
 
 ### DevOps & CI/CD
 
 - **Docker**: Multi-stage build with Eclipse Temurin Alpine images
 - **Docker Compose**: Local containerized deployment
 - **GitHub Actions**: CI pipeline with coverage reporting (Codecov, Codacy)
-- **Azure Pipelines**: Alternative CI configuration
 
 ## Project Structure
 
@@ -90,17 +89,18 @@ scripts/
 
 - **Lombok**: Prefer `@Data`, `@RequiredArgsConstructor`, `@NoArgsConstructor`, `@AllArgsConstructor` over manual code
 - **Streams**: Use Java Streams API for collection processing (see `BooksService.retrieveAll()`)
-- **Modern Java**: Leverage JDK 21 features (records, pattern matching, etc.) where beneficial
+- **Modern Java**: Leverage JDK 25 features (records, pattern matching, sealed classes, etc.) where beneficial
 - **Comments**: Section dividers used in controllers/services (e.g., `/* HTTP POST */`)
 
 ### Testing Conventions
 
 - **Test Class Naming**: `<ClassName>Tests` (plural, e.g., `BooksControllerTests`)
 - **Test Method Naming**: `given<Condition>_when<Action>_then<Expected>` (BDD style)
 - **Assertions**: Use AssertJ fluent assertions (`assertThat(...).isEqualTo(...)`)
-- **Mocking**: Use `@MockBean` for Spring beans, verify interactions with `verify()`
+- **Mocking**: Use `@MockitoBean` for Spring beans (new in Spring Boot 4.0), verify interactions with `verify()`
 - **Test Data**: Use fake data factories (`BookFakes`, `BookDTOFakes`) for consistent test data
 - **Display Names**: Use `@DisplayName` for readable test descriptions
+- **Caching in Tests**: Add `@AutoConfigureCache` to slice tests (`@WebMvcTest`, `@DataJpaTest`) when caching is needed
 
 ### Coverage Exclusions
 
@@ -137,8 +137,8 @@ JaCoCo excludes from coverage (see `pom.xml` and `codecov.yml`):
 **Critical Requirements**:
 
 - **ALWAYS use `./mvnw` wrapper** (Unix/macOS) or `mvnw.cmd` (Windows), NOT `mvn`
-- **JDK 21 is REQUIRED**: The project targets JDK 21 (LTS). Using newer JDKs (22+) will cause Mockito/ByteBuddy compatibility issues in tests
-- **JAVA_HOME must be set**: Maven wrapper requires JAVA_HOME pointing to JDK 21 installation
+- **JDK 25 is REQUIRED**: The project targets JDK 25 (LTS)
+- **JAVA_HOME must be set**: Maven wrapper requires JAVA_HOME pointing to JDK 25 installation
 
 ### Docker Commands
 
@@ -205,8 +205,8 @@ docker compose logs -f
 - **Lombok not working**: Ensure annotation processor is enabled in IDE and `maven-compiler-plugin` includes Lombok path
 - **Tests failing**: Check if H2 database is properly initialized; review `BooksDataInitializer.seed()`
 - **Port already in use**: Change `server.port` in `application.properties` or kill process using ports 9000/9001
-- **JAVA_HOME not set**: Run `export JAVA_HOME=$(/usr/libexec/java_home -v 21)` on macOS or set to JDK 21 path on other systems
-- **JDK version errors**: Project requires JDK 21 (LTS). Using JDK 22+ causes Mockito/ByteBuddy failures like "Java 25 (69) is not supported"
+- **JAVA_HOME not set**: Run `export JAVA_HOME=$(/usr/libexec/java_home -v 25)` on macOS or set to JDK 25 path on other systems
+- **CacheManager errors in tests**: Add `@AutoConfigureCache` annotation to slice tests (`@WebMvcTest`, `@DataJpaTest`)
 
 ### Docker Issues
 
@@ -216,10 +216,10 @@ docker compose logs -f
 ### Common Pitfalls
 
 - **Don't use system Maven**: Always use `./mvnw` wrapper
-- **Don't use newer JDKs**: Stick to JDK 21 - newer versions break Mockito in tests
 - **Don't modify `Application.java` coverage**: It's excluded by design
 - **Don't test Lombok-generated code**: Focus on business logic
 - **Repository interfaces**: Custom query methods may not show in coverage (JaCoCo limitation)
+- **Spring Boot 4.0 modular packages**: Test annotations like `@WebMvcTest`, `@DataJpaTest`, and `@AutoConfigureCache` are now in modular packages (e.g., `org.springframework.boot.webmvc.test.autoconfigure.WebMvcTest`)
 
 ## CI/CD Pipeline
 
@@ -235,11 +235,6 @@ docker compose logs -f
 - `CODACY_PROJECT_TOKEN`: Codacy integration token
 - `GITHUB_TOKEN`: Automatically provided for GHCR push
 
-### Azure Pipelines (`azure-pipelines.yml`)
-
-- Runs on `ubuntu-latest` with JDK 21
-- Executes `mvn package` and publishes test results
-
 ## Contributing
 
 Follow [Conventional Commits](https://www.conventionalcommits.org/):

.github/workflows/maven.yml

@@ -4,99 +4,99 @@
 name: Java CI
 
 permissions:
-  contents: read
+    contents: read
 
 on:
-  push:
-    branches: [master]
-  pull_request:
-    branches: [master]
+    push:
+        branches: [master]
+    pull_request:
+        branches: [master]
 
 env:
-  JAVA_VERSION: 21
+    JAVA_VERSION: 25
 
 jobs:
-  verify:
-    runs-on: ubuntu-latest
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v6.0.0
-
-      - name: Set up OpenJDK ${{ env.JAVA_VERSION }}
-        uses: actions/setup-java@v5.0.0
-        with:
-          java-version: ${{ env.JAVA_VERSION }}
-          distribution: "temurin"
-          cache: "maven"
-
-      - name: Compile and verify with Maven
-        run: mvn verify --file pom.xml
-
-      - name: Upload JaCoCo coverage report artifact
-        uses: actions/upload-artifact@v5.0.0
-        with:
-          name: jacoco.xml
-          path: ./target/site/jacoco/jacoco.xml
-
-  coverage:
-    needs: verify
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        service: [codecov, codacy]
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v6.0.0
-
-      - name: Download JaCoCo coverage report artifact
-        uses: actions/download-artifact@v6.0.0
-        with:
-          name: jacoco.xml
-
-      - name: Upload JaCoCo coverage report to Codecov
-        if: matrix.service == 'codecov'
-        uses: codecov/codecov-action@v5.5.1
-        with:
-          token: ${{ secrets.CODECOV_TOKEN }}
-          files: jacoco.xml
-
-      - name: Upload JaCoCo coverage report to Codacy
-        if: matrix.service == 'codacy'
-        uses: codacy/codacy-coverage-reporter-action@v1.3.0
-        with:
-          project-token: ${{ secrets.CODACY_PROJECT_TOKEN }}
-          force-coverage-parser: jacoco -r jacoco.xml
-
-  container:
-    needs: coverage
-    runs-on: ubuntu-latest
-    if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}
-
-    permissions:
-      contents: read
-      packages: write
-
-    steps:
-      - name: Checkout repository
-        uses: actions/checkout@v6.0.0
-
-      - name: Log in to GitHub Container Registry
-        uses: docker/login-action@v3.6.0
-        with:
-          registry: ghcr.io
-          username: ${{ github.actor }}
-          password: ${{ secrets.GITHUB_TOKEN }}
-
-      - name: Set up Docker Buildx
-        uses: docker/setup-buildx-action@v3.11.1
-
-      - name: Build and push Docker image to GitHub Container Registry
-        uses: docker/build-push-action@v6.18.0
-        with:
-          context: .
-          push: true
-          platforms: linux/amd64
-          provenance: false
-          tags: |
-            ghcr.io/${{ github.repository }}:latest
-            ghcr.io/${{ github.repository }}:sha-${{ github.sha }}
+    verify:
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout repository
+              uses: actions/checkout@v6.0.0
+
+            - name: Set up OpenJDK ${{ env.JAVA_VERSION }}
+              uses: actions/setup-java@v5.0.0
+              with:
+                  java-version: ${{ env.JAVA_VERSION }}
+                  distribution: "temurin"
+                  cache: "maven"
+
+            - name: Compile and verify with Maven
+              run: mvn verify --file pom.xml
+
+            - name: Upload JaCoCo coverage report artifact
+              uses: actions/upload-artifact@v5.0.0
+              with:
+                  name: jacoco.xml
+                  path: ./target/site/jacoco/jacoco.xml
+
+    coverage:
+        needs: verify
+        runs-on: ubuntu-latest
+        strategy:
+            matrix:
+                service: [codecov, codacy]
+        steps:
+            - name: Checkout repository
+              uses: actions/checkout@v6.0.0
+
+            - name: Download JaCoCo coverage report artifact
+              uses: actions/download-artifact@v6.0.0
+              with:
+                  name: jacoco.xml
+
+            - name: Upload JaCoCo coverage report to Codecov
+              if: matrix.service == 'codecov'
+              uses: codecov/codecov-action@v5.5.1
+              with:
+                  token: ${{ secrets.CODECOV_TOKEN }}
+                  files: jacoco.xml
+
+            - name: Upload JaCoCo coverage report to Codacy
+              if: matrix.service == 'codacy'
+              uses: codacy/codacy-coverage-reporter-action@v1.3.0
+              with:
+                  project-token: ${{ secrets.CODACY_PROJECT_TOKEN }}
+                  force-coverage-parser: jacoco -r jacoco.xml
+
+    container:
+        needs: coverage
+        runs-on: ubuntu-latest
+        if: ${{ github.event_name == 'push' && github.ref == 'refs/heads/master' }}
+
+        permissions:
+            contents: read
+            packages: write
+
+        steps:
+            - name: Checkout repository
+              uses: actions/checkout@v6.0.0
+
+            - name: Log in to GitHub Container Registry
+              uses: docker/login-action@v3.6.0
+              with:
+                  registry: ghcr.io
+                  username: ${{ github.actor }}
+                  password: ${{ secrets.GITHUB_TOKEN }}
+
+            - name: Set up Docker Buildx
+              uses: docker/setup-buildx-action@v3.11.1
+
+            - name: Build and push Docker image to GitHub Container Registry
+              uses: docker/build-push-action@v6.18.0
+              with:
+                  context: .
+                  push: true
+                  platforms: linux/amd64
+                  provenance: false
+                  tags: |
+                      ghcr.io/${{ github.repository }}:latest
+                      ghcr.io/${{ github.repository }}:sha-${{ github.sha }}

.java-version

@@ -1 +1 @@
-21
+25

Dockerfile

@@ -2,7 +2,7 @@
 # Stage 1: Builder
 # This stage builds the application and its dependencies.
 # ------------------------------------------------------------------------------
-FROM maven:3.9-eclipse-temurin-21-alpine AS builder
+FROM maven:3.9-eclipse-temurin-25-alpine AS builder
 
 WORKDIR /app
 
@@ -19,7 +19,7 @@ RUN mvn clean package -DskipTests
 # Stage 2: Runtime
 # This stage creates the final, minimal image to run the application.
 # ------------------------------------------------------------------------------
-FROM eclipse-temurin:21-jdk-alpine AS runtime
+FROM eclipse-temurin:25-jdk-alpine AS runtime
 
 WORKDIR /app
 
@@ -28,7 +28,7 @@ RUN apk add --no-cache curl
 
 # Metadata labels for the image. These are useful for registries and inspection.
 LABEL org.opencontainers.image.title="🧪 RESTful Web Service with Spring Boot"
-LABEL org.opencontainers.image.description="Proof of Concept for a RESTful Web Service made with JDK 21 (LTS) and Spring Boot 3"
+LABEL org.opencontainers.image.description="Proof of Concept for a RESTful Web Service made with JDK 25 (LTS) and Spring Boot 4"
 LABEL org.opencontainers.image.licenses="MIT"
 LABEL org.opencontainers.image.source="https://github.com/nanotaboada/java.samples.spring.boot"
 

README.md

@@ -7,7 +7,7 @@
 [![CodeFactor](https://www.codefactor.io/repository/github/nanotaboada/java.samples.spring.boot/badge)](https://www.codefactor.io/repository/github/nanotaboada/java.samples.spring.boot)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://opensource.org/licenses/MIT)
 
-> A production-ready RESTful Web Service demonstrating clean architecture patterns with Spring Boot 3, comprehensive testing, and containerized deployment.
+> A production-ready RESTful Web Service demonstrating clean architecture patterns with Spring Boot 4, comprehensive testing, and containerized deployment.
 
 ## Table of Contents
 
@@ -26,7 +26,7 @@
 
 ## About
 
-A proof-of-concept RESTful Web Service built with **Spring Boot 3** targeting **JDK 21 (LTS)**. This project demonstrates best practices for building a layered, testable, and maintainable API implementing CRUD operations for a Books resource.
+A proof-of-concept RESTful Web Service built with **Spring Boot 4** targeting **JDK 25 (LTS)**. This project demonstrates best practices for building a layered, testable, and maintainable API implementing CRUD operations for a Books resource.
 
 The service showcases:
 
@@ -48,7 +48,7 @@ The service showcases:
 - ✅ **Health Monitoring** - Spring Boot Actuator endpoints
 - ✅ **Test Coverage** - JaCoCo reports with Codecov/Codacy integration
 - ✅ **Docker Support** - Multi-stage builds with Eclipse Temurin Alpine images
-- ✅ **CI/CD Ready** - GitHub Actions and Azure Pipelines configurations
+- ✅ **CI/CD Ready** - GitHub Actions with automated testing and container builds
 
 ## Architecture
 
@@ -66,16 +66,15 @@ _Figure: Simplified, conceptual project structure and main application flow. Not
 
 Before you begin, ensure you have the following installed:
 
-- **Java Development Kit (JDK) 21** - [Download](https://adoptium.net/temurin/releases/?version=21)
-  - ⚠️ **Critical**: JDK 21 is required. Newer versions (22+) cause Mockito/ByteBuddy compatibility issues.
+- **Java Development Kit (JDK) 25** - [Download](https://adoptium.net/temurin/releases/?version=25)
   - Verify with: `java -version`
 - **Maven 3.9+** (optional) - Project includes Maven wrapper (`./mvnw`)
 - **Docker** (optional) - For containerized deployment
 
 **macOS Users**: Set `JAVA_HOME` if needed:
 
 ```bash
-export JAVA_HOME=$(/usr/libexec/java_home -v 21)
+export JAVA_HOME=$(/usr/libexec/java_home -v 25)
 ```
 
 ## Getting Started
@@ -180,8 +179,8 @@ open target/site/jacoco/index.html
 
 **Test Structure:**
 
-- **Unit Tests** - `@WebMvcTest`, `@DataJpaTest` for isolated layer testing
-- **Mocking** - Mockito for dependency mocking
+- **Unit Tests** - `@WebMvcTest`, `@DataJpaTest` for isolated layer testing (with `@AutoConfigureCache` for caching support)
+- **Mocking** - Mockito with `@MockitoBean` for dependency mocking
 - **Assertions** - AssertJ fluent assertions
 - **Naming Convention** - BDD style: `given<Condition>_when<Action>_then<Expected>`