Migrate from maven to gradle

.github/workflows/ci.yml

@@ -54,19 +54,14 @@ jobs:
         working-directory: log/native
         run: cargo build --release
 
-      - name: Set up Java 17
+      - name: Set up Java 24
         uses: actions/setup-java@v4
         with:
-          java-version: '17'
+          java-version: '24'
           distribution: 'temurin'
 
-      - name: Cache Maven local repository
-        uses: actions/cache@v4
-        with:
-          path: ~/.m2/repository
-          key: ${{ runner.os }}-maven-${{ hashFiles('**/pom.xml') }}
-          restore-keys: |
-            ${{ runner.os }}-maven-
+      - name: Setup Gradle
+        uses: gradle/actions/setup-gradle@v4
 
-      - name: Maven build and test
-        run: mvn verify -Djava.library.path=log/native/target/release
+      - name: Gradle build and test
+        run: ./gradlew build

.gitignore

@@ -6,13 +6,16 @@
 # Rust build artifacts
 target/
 
+# Gradle
+.gradle/
+build/
+
 # Java build artifacts
 *.class
 *.jar
+!gradle/wrapper/gradle-wrapper.jar
 *.war
 *.ear
-log/target/
-benchmark-driver/target/
 
 # Benchmark results
 *.json

AGENTS.md

@@ -31,7 +31,8 @@ opendata-java/
 │       ├── LogDbReader.java        # Read-only API
 │       ├── LogDbConfig.java        # Configuration record
 │       └── ...
-└── pom.xml                         # Maven multi-module build
+├── build.gradle                    # Gradle multi-module build
+└── settings.gradle
 ```
 
 ## JNI Architecture
@@ -92,8 +93,7 @@ The JNI layer prepends an 8-byte timestamp to values for latency measurement:
 ### Prerequisites
 
 - Rust stable toolchain
-- Java 17+
-- Maven 3.8+
+- Java 24+
 - Sibling clone of `opendata` repository
 
 ### Building
@@ -103,9 +103,9 @@ The JNI layer prepends an 8-byte timestamp to values for latency measurement:
 cd log/native
 cargo build --release
 
-# Build and install Java modules
+# Build Java modules
 cd ../..
-mvn clean install
+./gradlew build
 ```
 
 ### Testing
@@ -116,7 +116,7 @@ cd log/native
 cargo test
 
 # Java tests (requires native library)
-mvn test -Djava.library.path=log/native/target/release
+./gradlew test
 ```
 
 ### Formatting and Linting

CONTRIBUTING.md

@@ -50,8 +50,7 @@ Open an issue describing:
 ### Prerequisites
 
 - Rust stable toolchain ([rustup](https://rustup.rs/))
-- Java 17+ ([SDKMAN](https://sdkman.io/) recommended)
-- Maven 3.8+
+- Java 24+ ([SDKMAN](https://sdkman.io/) recommended)
 - Git
 - Local clone of [opendata](https://github.com/opendata-oss/opendata) as sibling directory
 
@@ -72,7 +71,7 @@ cargo build --release
 
 # Build Java modules
 cd ../..
-mvn clean install -DskipTests
+./gradlew build
 ```
 
 ## Code Style
@@ -154,7 +153,7 @@ cd log/native
 cargo test
 
 # Java tests (requires native library built)
-mvn test -Djava.library.path=log/native/target/release
+./gradlew test
 ```
 
 ## Pull Request Process

build.gradle

@@ -0,0 +1,38 @@
+subprojects {
+    apply plugin: 'java-library'
+
+    group = 'dev.opendata'
+    version = '0.1.0-SNAPSHOT'
+
+    def minimumJava = 24
+    def currentJava = JavaVersion.current()
+    def toolchainVersion = currentJava.isCompatibleWith(JavaVersion.toVersion(minimumJava))
+        ? Integer.parseInt(currentJava.majorVersion)
+        : minimumJava
+
+    java {
+        toolchain {
+            languageVersion = JavaLanguageVersion.of(toolchainVersion)
+        }
+        sourceCompatibility = JavaVersion.toVersion(minimumJava)
+        targetCompatibility = JavaVersion.toVersion(minimumJava)
+    }
+
+    tasks.withType(JavaCompile).configureEach {
+        options.release = minimumJava
+    }
+
+    repositories {
+        mavenCentral()
+    }
+
+    dependencies {
+        testImplementation 'org.junit.jupiter:junit-jupiter:5.10.2'
+        testImplementation 'org.assertj:assertj-core:3.25.3'
+        testRuntimeOnly 'org.junit.platform:junit-platform-launcher:1.10.2'
+    }
+
+    test {
+        useJUnitPlatform()
+    }
+}

common/build.gradle

@@ -0,0 +1,2 @@
+// Common utilities for OpenData Java bindings
+// Dependencies are configured in the root build.gradle

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.3.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

log/build.gradle

@@ -0,0 +1,8 @@
+dependencies {
+    implementation project(':common')
+}
+
+test {
+    jvmArgs "-Djava.library.path=${project.projectDir}/native/target/release"
+    jvmArgs '--enable-native-access=ALL-UNNAMED'
+}

settings.gradle

@@ -0,0 +1,6 @@
+plugins {
+    id 'org.gradle.toolchains.foojay-resolver-convention' version '1.0.0'
+}
+
+rootProject.name = 'opendata-java'
+include 'common', 'log'