Merge pull request #267 from ipfs-shipyard/fix/java-21

As we agreed, keep build-time requirements on LTS tools:
* Java 21+
* Maven 3.9.6 (see https://maveniverse.eu/blog/2026/01/15/maven-components-and-maximum-java-bytecode/) - in reality latest patch release (as of now 3.9.12) is preferred

Also document that this project classpath run time requirement is:
* Java 11+

Author: cstamas

.github/workflows/ci.yml

@@ -15,11 +15,11 @@ jobs:
 
     steps:
     - uses: actions/checkout@v6
-    - name: Set up JDK 11
+    - name: Set up JDK 21
       uses: actions/setup-java@v5
       with:
         distribution: temurin
-        java-version: 11
+        java-version: 21
         cache: 'maven'
     - name: Install and run IPFS
       run: ./install-run-ipfs.sh

README.md

@@ -47,11 +47,15 @@ for Maven, add the following sections to your pom.xml (replacing $LATEST_VERSION
 
 ### Building
 
+Build time requirements:
+* Java 21
+* Maven 3.9.6+ (latest patch release is recommended)
+
 * Clone this repository
-* Run `mvn install`
+* Run `./mvnw install`
 * Copy `target/ipfs-$VERSION.jar` into your project. Appropriate versions of other [dependencies](#dependencies) are also included in `dist/lib/`.
-* To copy the project and all dependency JARs to directory, execute `mvn eu.maveniverse.maven.plugins:toolbox:gav-copy -DsourceSpec="resolveTransitive(gav(com.github.ipfs:java-ipfs-http-client:v1.4.5-SNAPSHOT))" -DsinkSpec="flat(.)"` in that given directory.
-* Run tests using `mvn test` (invocation above will run them as well).
+* To copy the project and all dependency JARs to directory, execute `./mvnw eu.maveniverse.maven.plugins:toolbox:gav-copy -DsourceSpec="resolveTransitive(gav(com.github.ipfs:java-ipfs-http-client:v1.4.5-SNAPSHOT))" -DsinkSpec="flat(.)"` in that given directory.
+* Run tests using `./mvnw test` (invocation above will run them as well).
 
 ### Running tests
 
@@ -101,6 +105,9 @@ More example usage found [here](./src/main/java/io/ipfs/api/demo)
 
 ## Dependencies
 
+Run time requirements:
+* Java 11+
+
 Current versions of dependencies are listed in the `pom.xml`, their corresponding source repositories are:
 
 * [multibase](https://github.com/multiformats/java-multibase)

pom.xml

@@ -69,6 +69,30 @@
 
 	<build>
 		<plugins>
+			<plugin>
+				<groupId>org.apache.maven.plugins</groupId>
+				<artifactId>maven-enforcer-plugin</artifactId>
+				<version>3.6.2</version>
+				<configuration>
+					<rules>
+						<requireMavenVersion>
+							<version>3.9.6</version>
+						</requireMavenVersion>
+						<requireJavaVersion>
+							<version>21</version>
+						</requireJavaVersion>
+					</rules>
+				</configuration>
+				<executions>
+					<execution>
+						<id>enforce</id>
+						<goals>
+							<goal>enforce</goal>
+						</goals>
+						<phase>validate</phase>
+					</execution>
+				</executions>
+			</plugin>
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>