Server: upgrade to Java 21

Major features can be found here: https://advancedweb.hu/a-categorized-list-of-all-java-and-jvm-features-since-jdk-8-to-21/

Required companion upgrades:
  - Gradle 8.0.2 -> 8.4, see https://docs.gradle.org/8.4/userguide/upgrading_version_8.html for changes
  - Lombok 1.18.24 -> 1.18.30, see projectlombok/lombok#3393
  - Spring Boot 3.0.1 -> 3.1.4 to support new version of Lombok, see https://stackoverflow.com/a/77171271

.github/workflows/server-cd.yml

@@ -21,10 +21,10 @@ jobs:
       - name: checkout current repository
         uses: actions/checkout@v3
 
-      - name: set up Java 17
+      - name: set up Java 21
         uses: actions/setup-java@v3
         with:
-          java-version: '17'
+          java-version: '21'
           distribution: 'temurin'
 
       - name: build application jar

README.md

@@ -13,7 +13,7 @@ Deployment is automated using GitHub Actions and AWS. The deployed backend is
 containerized using Docker.
 
 ## Development
-To locally run this you need [Java 17](https://adoptium.net/), 
+To locally run this you need [Java](https://adoptium.net/), 
 [NodeJS](https://nodejs.org/en/),
 [Docker + Docker Compose](https://docs.docker.com/get-docker/) or [MariaDB](https://mariadb.org/download/),
 [Gradle](https://gradle.org/install/) (optional).

server/build.gradle

@@ -1,16 +1,16 @@
 plugins {
-    id 'org.springframework.boot' version '3.0.1'
+    id 'org.springframework.boot' version '3.1.4'
     id 'io.spring.dependency-management' version '1.1.0'
     id "com.gorylenko.gradle-git-properties" version "2.4.1"  // Used by Sentry to match errors to specific git commit
-    id "io.freefair.lombok" version "6.6.1"
+    id "io.freefair.lombok" version "8.4" // Lombok 1.18.30
     id 'java'
 }
 
 group = 'xyz.laane'
 version = '1.0.0'
 
 java {
-    sourceCompatibility = JavaVersion.VERSION_17
+    sourceCompatibility = JavaVersion.VERSION_21
 }
 
 repositories {

server/docker/Dockerfile

@@ -1,3 +1,3 @@
-FROM eclipse-temurin:17
+FROM eclipse-temurin:21
 COPY build/libs/*.jar app.jar
-ENTRYPOINT ["java", "-jar", "/app.jar", "--spring.profiles.active=prod"]
+ENTRYPOINT ["java", "-jar", "/app.jar", "--spring.profiles.active=prod"]

server/gradle/wrapper/gradle-wrapper.properties

@@ -1,6 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.0.2-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.4-all.zip
 networkTimeout=10000
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists