Build the project by JDK 21 as default

- Spotless is executed only on JDK 11+
- We have ITs executing on JDK 8

Author: slawekjaranowski

.github/workflows/maven.yml

@@ -42,13 +42,13 @@ jobs:
 
       - uses: actions/setup-java@v4
         with:
-          java-version: 8
+          java-version: 21
           distribution: 'zulu'
           cache: 'maven'
 
       - name: Set up Maven
         run:
-          mvn --errors --batch-mode --show-version org.apache.maven.plugins:maven-wrapper-plugin:3.3.2:wrapper "-Dmaven=3.9.9"
+          mvn --errors --batch-mode --show-version org.apache.maven.plugins:maven-wrapper-plugin:3.3.2:wrapper "-Dmaven=3.9.10"
 
       - name: Build with Maven
         run: ./mvnw verify -e -B -V -DdistributionFileName=apache-maven

Jenkinsfile

@@ -20,7 +20,7 @@
 properties([buildDiscarder(logRotator(artifactNumToKeepStr: '5', numToKeepStr: env.BRANCH_NAME=='maven-3.9.x'?'5':'1'))])
 
 def buildOs = 'linux'
-def buildJdk = '8'
+def buildJdk = '21'
 def buildMvn = '3.x.x'
 def runITsOses = ['linux']
 def runITsJdks = ['8', '11', '17']

maven-core/src/test/java/org/apache/maven/graph/DefaultProjectDependencyGraphTest.java

@@ -40,11 +40,12 @@ public class DefaultProjectDependencyGraphTest extends TestCase {
     private final MavenProject cProject = createProject(Arrays.asList(toDependency(bProject)), "cProject");
 
     private final MavenProject dProject = createProject(
-        Arrays.asList(toDependency(aProject), toDependency(bProject), toDependency(cProject)), "dProject");
+            Arrays.asList(toDependency(aProject), toDependency(bProject), toDependency(cProject)), "dProject");
 
     private final MavenProject eProject = createProject(
-        Arrays.asList(toDependency(aProject), toDependency(bProject), toDependency(cProject), toDependency(dProject)),
-        "eProject");
+            Arrays.asList(
+                    toDependency(aProject), toDependency(bProject), toDependency(cProject), toDependency(dProject)),
+            "eProject");
 
     private final MavenProject depender1 = createProject(Arrays.asList(toDependency(aProject)), "depender1");
 
@@ -90,8 +91,8 @@ public void testNonTransitiveFiltering() throws DuplicateProjectException, Cycle
     // downstream projects. Which would result in dProject and eProject being returned twice, but now the results are
     // made unique.
     public void testGetDownstreamDoesNotDuplicateProjects() throws CycleDetectedException, DuplicateProjectException {
-        ProjectDependencyGraph graph = new DefaultProjectDependencyGraph(
-            Arrays.asList(aProject, bProject, cProject, dProject, eProject));
+        ProjectDependencyGraph graph =
+                new DefaultProjectDependencyGraph(Arrays.asList(aProject, bProject, cProject, dProject, eProject));
         graph = new FilteredProjectDependencyGraph(graph, Arrays.asList(aProject, dProject, eProject));
         final List<MavenProject> downstreamProjects = graph.getDownstreamProjects(aProject, false);
         assertEquals(2, downstreamProjects.size());