Update mcr.microsoft.com/devcontainers/java Docker tag to v3

* Moving back to Java 17 compatibility. I'll change demo-remote a little later, because otherwise I have to break the project for some time.

* Prepares version 0.1.3

.devcontainer/devcontainer.json

@@ -1,6 +1,6 @@
 {
   "name": "Java",
-  "image": "mcr.microsoft.com/devcontainers/java:1-21",
+  "image": "mcr.microsoft.com/devcontainers/java:3-21",
   "features": {
     "ghcr.io/devcontainers/features/java:1": {
       "version": "none",

.idea/misc.xml

@@ -4,7 +4,7 @@
   <component name="FrameworkDetectionExcludesConfiguration">
     <file type="web" url="file://$PROJECT_DIR$" />
   </component>
-  <component name="ProjectRootManager" version="2" languageLevel="JDK_24" project-jdk-name="temurin-21" project-jdk-type="JavaSDK">
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" project-jdk-name="temurin-21" project-jdk-type="JavaSDK">
     <output url="file://$PROJECT_DIR$/out" />
   </component>
 </project>

CLAUDE.md

@@ -66,7 +66,8 @@ The parser extracts `meta[property^=og:]` tags and builds structured data models
 
 ## Development Notes
 
-- **JVM Toolchain**: Java 24 (see `jvmToolchain(24)` in build files)
+- **JVM Toolchain**: Java 17 (see `jvmToolchain(17)` in build files)
+- **Minimum Java Version**: Java 17 (required by Ksoup dependency)
 - **Testing**: CI matrix tests on Java 17 and 23 via GitHub Actions
 - **Dependencies**: Core library uses Ksoup (v0.2.5) for HTML parsing and network requests
 - **Maven Coordinates**: Group `fr.lengrand`, artifact `opengraphkt`, currently at `0.1.2-SNAPSHOT`

CONTRIBUTING.md

@@ -0,0 +1,158 @@
+# Contributing to OpenGraphKt
+
+Thank you for your interest in contributing to OpenGraphKt! This document provides guidelines and instructions for contributing to the project.
+
+## Development Setup
+
+### Prerequisites
+
+- Java 17 or later (JVM toolchain configured for Java 17)
+- Gradle 8.14.3+ (wrapper included)
+- Git
+
+### Getting Started
+
+1. Clone the repository:
+   ```bash
+   git clone https://github.com/jlengrand/OpenGraphKt.git
+   cd OpenGraphKt
+   ```
+
+2. Build the project:
+   ```bash
+   ./gradlew build
+   ```
+
+3. Run tests:
+   ```bash
+   ./gradlew test
+   ```
+
+4. Check code coverage:
+   ```bash
+   ./gradlew koverXmlReport
+   ./gradlew koverVerify  # Enforces 70% minimum coverage
+   ```
+
+## Project Structure
+
+- `opengraphkt/` - Core library module (published to Maven Central)
+- `demo/` - Local file parsing examples
+- `demo-remote/` - Remote URL parsing examples using published artifact
+- `scrape-test/` - Testing/scraping utilities
+
+## Making Changes
+
+### Code Style
+
+- Follow Kotlin coding conventions
+- Use meaningful variable and function names
+- Add KDoc comments for public APIs
+
+### Testing
+
+- Write tests for all new functionality
+- Maintain minimum 70% code coverage (enforced by Kover)
+- Run tests locally before submitting PR: `./gradlew test`
+
+### Commits
+
+- Write clear, concise commit messages
+- Reference issue numbers when applicable
+- Keep commits focused and atomic
+
+## Submitting Changes
+
+1. Fork the repository
+2. Create a feature branch: `git checkout -b feature/your-feature-name`
+3. Make your changes
+4. Run tests and ensure coverage: `./gradlew test koverVerify`
+5. Commit your changes
+6. Push to your fork
+7. Submit a Pull Request
+
+## Publishing New Versions
+
+This section is for maintainers only.
+
+### Version Numbering
+
+OpenGraphKt follows [Semantic Versioning](https://semver.org/):
+- **MAJOR** version for incompatible API changes
+- **MINOR** version for backwards-compatible functionality additions
+- **PATCH** version for backwards-compatible bug fixes
+
+### Pre-Release Checklist
+
+1. **Update version number** in `opengraphkt/build.gradle.kts`:
+   ```kotlin
+   version = "0.1.3-SNAPSHOT"  // Change to "0.1.3" for release
+   ```
+
+2. **Update demo-remote dependency** in `demo-remote/build.gradle.kts`:
+   ```kotlin
+   dependencies {
+       implementation("fr.lengrand:opengraphkt:0.1.3")  // Match release version
+   }
+   ```
+
+3. **Run full test suite**:
+   ```bash
+   ./gradlew clean build test koverVerify
+   ```
+
+4. **Test demo applications**:
+   ```bash
+   ./gradlew :demo:run
+   ./gradlew :demo-remote:run
+   ```
+
+### Publishing to Maven Central
+
+The project uses the `com.vanniktech.maven.publish` plugin for publishing. Publishing is automated through GitHub Actions.
+
+1. **Bump version ** in `opengraphkt/build.gradle.kts`:
+   ```kotlin
+   version = "0.1.4"
+   ```
+
+2. **Publish to local Maven for testing** (optional):
+   ```bash
+   ./gradlew publishToMavenLocal
+   ```
+
+3. **Create GitHub release** (this triggers the publishing workflow):
+   - Go to GitHub repository → Releases → "Draft a new release"
+   - Click "Choose a tag" and create a new tag (e.g., `v0.1.3`)
+   - Set the release title (e.g., `v0.1.3`)
+   - Add release notes describing changes
+   - Click "Publish release"
+
+4. **GitHub Actions will automatically**:
+   - Build the project
+   - Run tests
+   - Publish to Maven Central
+   - The workflow is triggered automatically when you create a new release
+
+5. After a few minutes, you will see the new version in [Maven Central](https://mvnrepository.com/artifact/fr.lengrand/opengraphkt). You can also directly check the real-time status on [Central Sonartype](https://central.sonatype.com/publishing/deployments).
+
+### Post-Release Steps
+
+1. **Bump version to next SNAPSHOT** in `opengraphkt/build.gradle.kts`:
+   ```kotlin
+   version = "0.1.5-SNAPSHOT"
+   ```
+
+2. **Commit version bump**:
+   ```bash
+   git commit -am "Bump version to 0.1.5-SNAPSHOT"
+   git push
+   ```
+
+## Questions?
+
+If you have questions or need help, please:
+- Open an issue on GitHub
+- Check existing issues and discussions
+
+Thank you for contributing to OpenGraphKt!

demo-remote/build.gradle.kts

@@ -10,7 +10,7 @@ repositories {
 }
 
 dependencies {
-    implementation("fr.lengrand:opengraphkt:0.1.0")
+    implementation("fr.lengrand:opengraphkt:0.1.3")
     testImplementation(kotlin("test"))
 }
 
@@ -19,9 +19,9 @@ tasks.test {
 }
 
 kotlin {
-    jvmToolchain(24)
+    jvmToolchain(17)
 }
 
 application {
-    mainClass = "fr.lengrand.opengraphkt.MainKt"
+    mainClass = "fr.lengrand.opengraphktremote.MainKt"
 }

demo/build.gradle.kts

@@ -24,7 +24,7 @@ tasks.test {
 }
 
 kotlin {
-    jvmToolchain(24)
+    jvmToolchain(17)
 }
 
 application {

opengraphkt/build.gradle.kts

@@ -1,13 +1,11 @@
-import com.vanniktech.maven.publish.SonatypeHost
-
 plugins {
     kotlin("jvm")
-    id("com.vanniktech.maven.publish") version "0.32.0"
-    id("org.jetbrains.kotlinx.kover") version "0.9.1"
+    id("com.vanniktech.maven.publish") version "0.34.0"
+    id("org.jetbrains.kotlinx.kover") version "0.9.3"
 }
 
 group = "fr.lengrand"
-version = "0.1.2"
+version = "0.1.4-SNAPSHOT"
 
 repositories {
     mavenCentral()
@@ -35,12 +33,20 @@ tasks.jar {
     }
 }
 
+java {
+    sourceCompatibility = JavaVersion.VERSION_17
+    targetCompatibility = JavaVersion.VERSION_17
+}
+
 kotlin {
-    jvmToolchain(24)
+    jvmToolchain(17)
+    compilerOptions {
+        jvmTarget.set(org.jetbrains.kotlin.gradle.dsl.JvmTarget.JVM_17)
+    }
 }
 
 mavenPublishing {
-    publishToMavenCentral(SonatypeHost.CENTRAL_PORTAL)
+    publishToMavenCentral()
 
     signAllPublications()
 

scrape-test/build.gradle.kts

@@ -24,5 +24,5 @@ tasks.test {
     useJUnitPlatform()
 }
 kotlin {
-    jvmToolchain(24)
+    jvmToolchain(17)
 }