Move to JDK 25 and Gradle 9.8.1

Gradle 8.12 cannot read Java 25 class files (major version 69), so the
build failed at script compilation. Upgrade the wrapper to 9.8.1, bump
Mockito to 5.24.0 for a Byte Buddy that supports Java 25, and order
warUnversioned after fatJar to satisfy Gradle 9 task validation.
Update CI, Dockerfile and docs to JDK 25.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TQYQFuCCtK2eoeXYYK5L4P

Author: sampottinger

.github/workflows/build.yaml

@@ -53,8 +53,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Setup pnpm
         run: npm install -g pnpm@10.20.0
       - name: Install node deps
@@ -87,8 +87,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Build fat jar
         run: ./gradlew fatJar
       - name: Install sshpass
@@ -119,8 +119,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Check grammar
         run: ./gradlew generateGrammarSource
       - name: Check main style
@@ -143,8 +143,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Run tests
         run: ./gradlew test
   runEngineLocal:
@@ -163,8 +163,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Download fatJar
         run: |
           mkdir -p build/libs
@@ -201,8 +201,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Download fatJar
         run: |
           mkdir -p build/libs
@@ -242,8 +242,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Build war
         run: ./gradlew warUnversioned
       - name: Install sshpass
@@ -269,8 +269,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Setup pnpm
         run: npm install -g pnpm@10.20.0
       - name: Download war
@@ -307,8 +307,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Generate Javadoc
         run: ./gradlew javadoc
       - name: Install sshpass
@@ -419,8 +419,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Setup pnpm
         run: npm install -g pnpm@10.20.0
       - name: Install SSH client and sshpass
@@ -605,8 +605,8 @@ jobs:
           git checkout ${{ github.sha }}
       - name: Setup Java
         run: |
-          echo "JAVA_HOME=$JAVA_HOME_21_X64" >> $GITHUB_ENV
-          echo "$JAVA_HOME_21_X64/bin" >> $GITHUB_PATH
+          echo "JAVA_HOME=$JAVA_HOME_25_X64" >> $GITHUB_ENV
+          echo "$JAVA_HOME_25_X64/bin" >> $GITHUB_PATH
       - name: Publish
         env:
           USERNAME: ${{ github.actor }}

CONTRIBUTING.md

@@ -104,7 +104,7 @@ Please reach out if you have further questions about these guidelines or want to
 ## Scope
 There are some limitations of scope for this project:
 
- - The Java engine must remain compatible with Java 21+ to support TeaVM compilation to WebAssembly but earlier versions are not guaranteed to be supported.
+ - The Java engine must remain compatible with Java 25+ to support TeaVM compilation to WebAssembly but earlier versions are not guaranteed to be supported.
  - Breaking changes to the QubecTalk language syntax should be discussed in an issue before implementation and require community input.
  - We must maintain both the browser-based application and standalone JAR/Docker execution paths but other execution modalities are currently out of scope.
  - Energy consumption can be modeled but energy mix for secondary emissions is currently considered out of scope.

DEVELOPING.md

@@ -12,7 +12,7 @@ Kigali Sim is organized into three main components and most have additional READ
 
 The **Java Engine** (`engine` directory) provides the primary computational mechanism for running simulations. There are different entrypoints depending on how Kiglai Sim is running like via WASM or JVM. That said, developers may wish to review the [Engine JavaDoc](https://kigalisim.org/guide/javadoc/org/kigalisim/engine/Engine.html). The **ECMAScript Editor** (`editor` directory) may be explored via the [Editor JSDoc](https://kigalisim.org/guide/jsdoc/). At a glance:
 
-- Core simulation engine built with Java 21+
+- Core simulation engine built with Java 25+
 - Uses ANTLR4 for parsing the QubecTalk domain specific language (DSL)
 - Contains the authoritative QubecTalk.g4 grammar file
 - Compiled to WebAssembly using TeaVM for browser execution
@@ -37,7 +37,7 @@ Both dev containers and local setup are supported, per developer preference.
 
 The project includes a dev container which is compatible with IntelliJ, VS Code, and GitHub Codespaces. As described in `.devcontainer`, this provides a reproducible development environment with dependencies required for most development activities pre-installed. Indeed, this guide was written from a dev container! It uses:
 
-- Debian 12 (bookworm-slim) with Eclipse Temurin JDK 21
+- Debian 12 (bookworm-slim) with Eclipse Temurin JDK 25
 - Node.js 18.x LTS (official Debian package)
 - pnpm 10.20.0 (installed via npm)
 - Chromium browser (official Debian package) for running tests
@@ -56,7 +56,7 @@ The container configuration prioritizes security by using only official package
 ### Local Setup
 You are very welcome to set up your own environment outside of a pre-prepared container. You will need the following:
 
-- Java JDK 21 or higher (please use only OpenJDK or similar, see [Adoptium](https://adoptium.net/))
+- Java JDK 25 or higher (please use only OpenJDK or similar, see [Adoptium](https://adoptium.net/))
 - Node.js 18.x and pnpm
 - Python 3.x (for local development server)
 

Dockerfile

@@ -1,5 +1,5 @@
-# Use Eclipse Temurin JDK 21 as base image
-FROM eclipse-temurin:21-jre
+# Use Eclipse Temurin JDK 25 as base image
+FROM eclipse-temurin:25-jre
 
 # Install wget for downloading the jar file
 RUN apt-get update && apt-get install -y wget

README.md

@@ -1,7 +1,7 @@
 # Kigali Sim
 Open source engine for simulating substances, applications, and policies relevant to the Montreal Protocol and the Kigali Amendment.
 
-[![Project Status: Active – The project has reached a stable, usable state and is being actively developed.](https://www.repostatus.org/badges/latest/active.svg)](https://www.repostatus.org/#active) [![BSD Licensed](https://img.shields.io/badge/License-BSD_3--Clause-blue.svg)](https://opensource.org/licenses/BSD-3-Clause) [![Build](https://github.com/SchmidtDSE/kigali-sim/actions/workflows/build.yaml/badge.svg?branch=deploy)](https://github.com/SchmidtDSE/kigali-sim/actions/workflows/build.yaml) ![Temurin 21 or higher](https://img.shields.io/badge/Java-Temurin%2021%2B-blue) [![status](https://joss.theoj.org/papers/eafc95ac66aae284563f36fa60f0261d/status.svg)](https://joss.theoj.org/papers/eafc95ac66aae284563f36fa60f0261d)
+[![Project Status: Active – The project has reached a stable, usable state and is being actively developed.](https://www.repostatus.org/badges/latest/active.svg)](https://www.repostatus.org/#active) [![BSD Licensed](https://img.shields.io/badge/License-BSD_3--Clause-blue.svg)](https://opensource.org/licenses/BSD-3-Clause) [![Build](https://github.com/SchmidtDSE/kigali-sim/actions/workflows/build.yaml/badge.svg?branch=deploy)](https://github.com/SchmidtDSE/kigali-sim/actions/workflows/build.yaml) ![Temurin 25 or higher](https://img.shields.io/badge/Java-Temurin%2025%2B-blue) [![status](https://joss.theoj.org/papers/eafc95ac66aae284563f36fa60f0261d/status.svg)](https://joss.theoj.org/papers/eafc95ac66aae284563f36fa60f0261d)
 
 <br>
 

engine/.idea/misc.xml

@@ -25,8 +25,8 @@ eclipse {
 }
 
 java {
-  sourceCompatibility = JavaVersion.VERSION_21
-  targetCompatibility = JavaVersion.VERSION_21
+  sourceCompatibility = JavaVersion.VERSION_25
+  targetCompatibility = JavaVersion.VERSION_25
 }
 
 repositories {
@@ -48,8 +48,8 @@ dependencies {
   // Testing dependencies
   testImplementation(platform("org.junit:junit-bom:5.12.1"))
   testImplementation("org.junit.jupiter:junit-jupiter")
-  testImplementation("org.mockito:mockito-core:5.16.1")
-  testImplementation("org.mockito:mockito-junit-jupiter:5.16.1")
+  testImplementation("org.mockito:mockito-core:5.24.0")
+  testImplementation("org.mockito:mockito-junit-jupiter:5.24.0")
   testRuntimeOnly("org.junit.platform:junit-platform-launcher")
 
   // Command line parsing
@@ -142,6 +142,7 @@ task fatJar(type: Copy) {
 // War unversioned
 task warUnversioned(type: Copy) {
   dependsOn war
+  mustRunAfter fatJar
   from war.archiveFile
   into file("${buildDir}/libs")
   rename { "KigaliSim.war" }

engine/build.gradle

@@ -1,7 +1,7 @@
 #Sun Jun 15 16:17:00 UTC 2025
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-8.12-bin.zip
-distributionSha256Sum=7a00d51fb93147819aab76024feece20b6b84e420694101f276be952e08bef03
+distributionSha256Sum=dce76f55f8e251a3a1f130eb120f30b3d271de2b76c9b0729d316b5a1b6dc01f
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.8.1-bin.zip
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists