Upgrade to Spring boot 4

build.gradle.kts

@@ -1,7 +1,7 @@
 import com.google.protobuf.gradle.id
 
 plugins {
-    id("org.springframework.boot") version "3.5.8"
+    id("org.springframework.boot") version "4.0.0"
     id("io.spring.dependency-management") version "1.1.7"
     id("org.graalvm.buildtools.native") version "0.11.1"
     id("org.jetbrains.kotlin.jvm") version "2.2.21"
@@ -26,22 +26,21 @@ repositories {
     mavenCentral()
 }
 
-extra["testcontainersVersion"] = "2.0.2"
-extra["jjwtVersion"] = "0.12.6"
+extra["testcontainersVersion"] = "1.21.3"
+extra["jjwtVersion"] = "0.13.0"
 
 dependencies {
     // Spring Boot Starters
-    implementation("org.springframework.boot:spring-boot-starter-web") {
-        exclude(group = "org.springframework.boot", module = "spring-boot-starter-tomcat")
-    }
-    implementation("org.springframework.boot:spring-boot-starter-undertow")
+    implementation("org.springframework.boot:spring-boot-starter-webmvc")
     implementation("org.springframework.boot:spring-boot-starter-data-jpa")
     implementation("org.springframework.boot:spring-boot-starter-security")
     implementation("org.springframework.boot:spring-boot-starter-validation")
     implementation("org.springframework.boot:spring-boot-starter-actuator")
-    implementation("org.springdoc:springdoc-openapi-starter-webmvc-ui:2.8.14")
+    implementation("org.springframework.boot:spring-boot-starter-jackson")
+    implementation("org.springdoc:springdoc-openapi-starter-webmvc-ui:3.0.0")
 
     // Database
+    implementation("org.springframework.boot:spring-boot-starter-flyway")
     runtimeOnly("org.postgresql:postgresql:42.7.8")
     runtimeOnly("org.flywaydb:flyway-database-postgresql:11.11.1")
 
@@ -56,31 +55,28 @@ dependencies {
     developmentOnly("org.springframework.boot:spring-boot-docker-compose")
 
     // Testing
-    testImplementation("org.springframework.boot:spring-boot-starter-test") {
-        exclude(group = "junit", module = "junit")
-    }
+    testImplementation("org.springframework.boot:spring-boot-starter-webmvc-test")
+    testImplementation("org.springframework.boot:spring-boot-starter-webflux-test")  // For WebTestClient
+    testImplementation("org.springframework.boot:spring-boot-starter-data-jpa-test")
     testImplementation("org.springframework.security:spring-security-test")
     testImplementation("org.springframework.boot:spring-boot-testcontainers")
     testImplementation("org.junit.jupiter:junit-jupiter:5.13.3")
     testImplementation("org.testcontainers:junit-jupiter")
     testImplementation("org.testcontainers:postgresql")
-    testImplementation("io.rest-assured:rest-assured:5.5.6")
-    testImplementation("io.rest-assured:json-path:5.5.6")
 
     // Swagger
     implementation("io.swagger.core.v3:swagger-models:2.2.34")
     implementation("io.swagger.core.v3:swagger-core:2.2.34")
-    implementation("javax.xml.bind:jaxb-api:2.3.1")
-    implementation("com.sun.xml.bind:jaxb-impl:2.3.9")
+    implementation("jakarta.xml.bind:jakarta.xml.bind-api:4.0.2")
+    runtimeOnly("org.glassfish.jaxb:jaxb-runtime:4.0.5")
 
     // gRPC and Protobuf
     implementation("io.grpc:grpc-netty-shaded:1.77.0")
     implementation("io.grpc:grpc-protobuf:1.77.0")
     implementation("io.grpc:grpc-stub:1.77.0")
     implementation("com.google.protobuf:protobuf-java:4.33.1")
-    // Because protobuf is still using javax annotations
-    implementation("javax.annotation:javax.annotation-api:1.3.2")
-    implementation("net.devh:grpc-server-spring-boot-starter:3.1.0.RELEASE")
+    implementation("jakarta.annotation:jakarta.annotation-api:3.0.0")
+    implementation("org.springframework.grpc:spring-grpc-spring-boot-starter:1.0.0")
 }
 
 dependencyManagement {

docs/troubleshooting.md

@@ -2,7 +2,17 @@
 
 Move `@EnableJpaAuditing` to a separate configuration class `JpaAuditingConfig.java` so that we can exclude it from
 testings. Otherwise it will throw errors when testing controllers:
+
 ```
 Caused by: java.lang.IllegalArgumentException: JPA metamodel must not be empty
 	at org.springframework.util.Assert.notEmpty(Assert.java:398)
 ```
+
+## Rest Assured - not support Spring Boot 4
+
+Rest Assured 5.5.6 doesn't work with Groovy 5 (still use Groovy 4), which is not compatible with Spring Boot 4(uses
+Groovy 5).
+We need to replace Rest Assured with `WebTestClient` before Rest Assured's upgrade.
+
+- [Remove integration for REST Docs' REST Assured support until REST Assured supports Groovy 5](https://github.com/spring-projects/spring-boot/issues/47685)
+- [Drop support for REST Assured until it supports Groovy 5](https://github.com/spring-projects/spring-restdocs/issues/1000)

gradle/jacoco.gradle.kts

@@ -61,7 +61,7 @@ val strictCoverageClasses = listOf(
 )
 
 tasks.named<JacocoReport>("jacocoTestReport") {
-    dependsOn(tasks.named("test"))
+    dependsOn(tasks.named("test"), tasks.named("processResources"), tasks.named("compileJava"))
     reports {
         xml.required.set(true)      // For CI/CD integration
         html.required.set(true)     // For human-readable reports

src/main/java/org/nkcoder/infrastructure/config/ObservabilityConfig.java

@@ -3,7 +3,7 @@
 import io.micrometer.core.aop.TimedAspect;
 import io.micrometer.core.instrument.MeterRegistry;
 import io.micrometer.core.instrument.config.MeterFilter;
-import org.springframework.boot.actuate.autoconfigure.metrics.MeterRegistryCustomizer;
+import org.springframework.boot.micrometer.metrics.autoconfigure.MeterRegistryCustomizer;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
 

src/main/java/org/nkcoder/infrastructure/security/JwtAuthenticationEntryPoint.java

@@ -1,6 +1,5 @@
 package org.nkcoder.infrastructure.security;
 
-import com.fasterxml.jackson.databind.ObjectMapper;
 import io.jsonwebtoken.ExpiredJwtException;
 import jakarta.servlet.http.HttpServletRequest;
 import jakarta.servlet.http.HttpServletResponse;
@@ -13,6 +12,7 @@
 import org.springframework.security.core.AuthenticationException;
 import org.springframework.security.web.AuthenticationEntryPoint;
 import org.springframework.stereotype.Component;
+import tools.jackson.databind.ObjectMapper;
 
 @Component
 public class JwtAuthenticationEntryPoint implements AuthenticationEntryPoint {

src/main/resources/application.yml

@@ -27,29 +27,23 @@ spring:
           fetch_size: 100
         generate_statistics: false
 
-  security:
-    oauth2:
-      resourceserver:
-        jwt:
-          issuer-uri: http://localhost:3001
-
-  jackson:
-    serialization:
-      write-dates-as-timestamps: false
-    time-zone: UTC
-    property-naming-strategy: LOWER_CAMEL_CASE
-
-  autoconfigure:
-    exclude:
-      - org.springframework.boot.autoconfigure.gson.GsonAutoConfiguration
-
   docker:
     compose:
       enabled: false
+
   threads:
     virtual:
       enabled: true
 
+  # gRPC configuration
+  grpc:
+    server:
+      port: 9090
+      max-inbound-message-size: 4MB
+      max-inbound-metadata-size: 8KB
+      reflection:
+        enabled: true
+
 # JWT Configuration
 jwt:
   secret:
@@ -68,10 +62,6 @@ cors:
   allow-credentials: true
   max-age: 3600
 
-# Rate Limiting Configuration
-rate-limit:
-  requests-per-window: 100
-  window-size-minutes: 15
 
 # Actuator Configuration
 management:
@@ -117,12 +107,4 @@ info:
     version: '@project.version@'
     description: '@project.description@'
     java-version: '@java.version@'
-    spring-boot-version: '@parent.version@'
-
-# grpc configuration
-grpc:
-  server:
-    port: 9090
-    max-inbound-message-size: 4194304  # 4MB
-    max-inbound-metadata-size: 8192    # 8KB
-    reflection-service-enabled: true
+    spring-boot-version: '@parent.version@'

src/test/java/org/nkcoder/infrastructure/config/DataJpaIntegrationTest.java

@@ -4,8 +4,8 @@
 import java.lang.annotation.Retention;
 import java.lang.annotation.RetentionPolicy;
 import java.lang.annotation.Target;
-import org.springframework.boot.test.autoconfigure.jdbc.AutoConfigureTestDatabase;
-import org.springframework.boot.test.autoconfigure.orm.jpa.DataJpaTest;
+import org.springframework.boot.data.jpa.test.autoconfigure.DataJpaTest;
+import org.springframework.boot.jdbc.test.autoconfigure.AutoConfigureTestDatabase;
 import org.springframework.context.annotation.Import;
 import org.springframework.data.jpa.repository.config.EnableJpaAuditing;
 import org.springframework.test.context.ActiveProfiles;