[POC] Migrate to Java 21 - code

.github/workflows/maven.yml

@@ -33,7 +33,7 @@ jobs:
       - name: Set up JDK
         uses: actions/setup-java@v4
         with:
-          java-version: 17
+          java-version: 21
           distribution: 'temurin'
 
       - name: Checkout maven

README.md

@@ -66,7 +66,7 @@ Do you like Apache Maven? Then [donate back to the ASF](https://www.apache.org/f
 Quick Build
 -------
 If you want to bootstrap Maven, you'll need:
-- Java 17+
+- Java 21+
 - Maven 3.6.3 or later
 - Run Maven, specifying a location into which the completed Maven distro should be installed:
     ```

apache-maven/pom.xml

@@ -118,16 +118,19 @@ under the License.
     <dependency>
       <groupId>javax.annotation</groupId>
       <artifactId>javax.annotation-api</artifactId>
+      <version>1.3.2</version>
     </dependency>
 
     <!-- DI Runtime -->
     <dependency>
       <groupId>org.eclipse.sisu</groupId>
       <artifactId>org.eclipse.sisu.plexus</artifactId>
+      <version>0.9.0.M3</version>
     </dependency>
     <dependency>
       <groupId>org.eclipse.sisu</groupId>
       <artifactId>org.eclipse.sisu.inject</artifactId>
+      <version>0.9.0.M3</version>
       <classifier>no_asm</classifier>
     </dependency>
     <dependency>

apache-maven/src/assembly/maven/bin/mvn

@@ -108,7 +108,7 @@ else
 fi
 
 if ! "$JAVACMD" --enable-native-access=ALL-UNNAMED -version >/dev/null 2>&1; then
-  echo "Error: Apache Maven 4.x requires Java 17 or newer to run." >&2
+  echo "Error: Apache Maven 4.x requires Java 21 or newer to run." >&2
   "$JAVACMD" -version >&2
   echo "Please upgrade your Java installation or set JAVA_HOME to point to a compatible JDK." >&2
   exit 1

apache-maven/src/assembly/maven/bin/mvn.cmd

@@ -70,10 +70,10 @@ if not exist "%JAVACMD%" (
   goto error
 )
 
-@REM Check Java version by testing the Java 17+ flag
+@REM Check Java version by testing the Java 21+ flag
 "%JAVACMD%" --enable-native-access=ALL-UNNAMED -version >nul 2>&1
 if ERRORLEVEL 1 (
-    echo Error: Apache Maven 4.x requires Java 17 or newer to run. >&2
+    echo Error: Apache Maven 4.x requires Java 21 or newer to run. >&2
     "%JAVACMD%" -version >&2
     echo Please upgrade your Java installation or set JAVA_HOME to point to a compatible JDK. >&2
     goto error

api/maven-api-core/src/main/java/org/apache/maven/api/services/MessageBuilder.java

@@ -245,15 +245,15 @@ default MessageBuilder newline() {
 
     /**
      * Append formatted content to the buffer.
-     * @see String#format(String, Object...)
+     * @see String#formatted(Object...)
      *
      * @param pattern a <a href="../util/Formatter.html#syntax">format string</a>
      * @param args arguments referenced by the format specifiers in the format string
      * @return the current builder
      */
     @Nonnull
     default MessageBuilder format(String pattern, Object... args) {
-        return append(String.format(pattern, args));
+        return append(pattern.formatted(args));
     }
 
     /**

api/maven-api-core/src/main/java/org/apache/maven/api/services/ProblemCollector.java

@@ -274,7 +274,7 @@ private boolean dropProblemWithLowerSeverity(BuilderProblem.Severity severity) {
                     List<P> problems = getProblems(s);
                     while (!problems.isEmpty()) {
                         try {
-                            return problems.remove(0) != null;
+                            return problems.removeFirst() != null;
                         } catch (IndexOutOfBoundsException e) {
                             // empty, continue
                         }

api/maven-api-core/src/main/java/org/apache/maven/api/services/VersionRangeResolverResult.java

@@ -65,7 +65,7 @@ public interface VersionRangeResolverResult extends Result<VersionRangeResolverR
     default Optional<Version> getLowestVersion() {
         return getVersions().isEmpty()
                 ? Optional.empty()
-                : Optional.of(getVersions().get(0));
+                : Optional.of(getVersions().getFirst());
     }
 
     /**

api/maven-api-core/src/test/java/org/apache/maven/api/services/SourcesTest.java

@@ -22,7 +22,6 @@
 import java.io.InputStream;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.io.TempDir;
@@ -44,7 +43,7 @@ class SourcesTest {
 
     @Test
     void testFromPath() {
-        Path path = Paths.get("/tmp");
+        Path path = Path.of("/tmp");
         Source source = Sources.fromPath(path);
 
         assertNotNull(source);
@@ -54,7 +53,7 @@ void testFromPath() {
 
     @Test
     void testBuildSource() {
-        Path path = Paths.get("/tmp");
+        Path path = Path.of("/tmp");
         ModelSource source = Sources.buildSource(path);
 
         assertNotNull(source);
@@ -64,7 +63,7 @@ void testBuildSource() {
 
     @Test
     void testResolvedSource() {
-        Path path = Paths.get("/tmp");
+        Path path = Path.of("/tmp");
         String location = "custom-location";
         ModelSource source = Sources.resolvedSource(path, location);
 
@@ -77,7 +76,7 @@ void testResolvedSource() {
     @Test
     void testPathSourceFunctionality() {
         // Test basic source functionality
-        Path path = Paths.get("/tmp");
+        Path path = Path.of("/tmp");
         Sources.PathSource source = (Sources.PathSource) Sources.fromPath(path);
 
         assertEquals(path.normalize(), source.getPath());
@@ -91,9 +90,9 @@ void testPathSourceFunctionality() {
     @Test
     void testBuildPathSourceFunctionality() {
         // Test build source functionality
-        Path basePath = Paths.get("/tmp");
+        Path basePath = Path.of("/tmp");
         ModelSource.ModelLocator locator = mock(ModelSource.ModelLocator.class);
-        Path resolvedPath = Paths.get("/tmp/subproject/pom.xml");
+        Path resolvedPath = Path.of("/tmp/subproject/pom.xml");
         when(locator.locateExistingPom(any(Path.class))).thenReturn(resolvedPath);
 
         Sources.BuildPathSource source = (Sources.BuildPathSource) Sources.buildSource(basePath);
@@ -109,7 +108,7 @@ void testBuildPathSourceFunctionality() {
     @Test
     void testResolvedPathSourceFunctionality() {
         // Test resolved source functionality
-        Path path = Paths.get("/tmp");
+        Path path = Path.of("/tmp");
         String location = "custom-location";
         Sources.ResolvedPathSource source = (Sources.ResolvedPathSource) Sources.resolvedSource(path, location);
 

api/maven-api-di/pom.xml

@@ -33,4 +33,11 @@
   <properties>
     <maven.compiler.proc>none</maven.compiler.proc>
   </properties>
+  <dependencies>
+    <dependency>
+      <groupId>jakarta.annotation</groupId>
+      <artifactId>jakarta.annotation-api</artifactId>
+      <version>1.3.5</version>
+    </dependency>
+  </dependencies>
 </project>

api/maven-api-model/src/main/java/org/apache/maven/api/model/InputLocation.java

@@ -201,6 +201,6 @@ public interface StringFormatter {
 
     @Override
     public String toString() {
-        return String.format("%s @ %d:%d", source != null ? source.getLocation() : "n/a", lineNumber, columnNumber);
+        return "%s @ %d:%d".formatted(source != null ? source.getLocation() : "n/a", lineNumber, columnNumber);
     }
 }

api/maven-api-model/src/main/mdo/maven.mdo

@@ -2107,7 +2107,7 @@
 
             <p>If a target version, different from the base version, is specified for resources or script files,
             then this value modifies the directory where the files will be copied.
-            For example, if {@code targetVersion} is 17, then the {@code foo/bar.properties}
+            For example, if {@code targetVersion} is 21, then the {@code foo/bar.properties}
             resource file will be copied as {@code META-INF/versions/17/foo/bar.properties}.</p>
 
             <p>This element can be combined with the {@code module} element for specifying sources,

compat/maven-artifact/src/main/java/org/apache/maven/artifact/repository/ArtifactRepository.java

@@ -19,7 +19,6 @@
 package org.apache.maven.artifact.repository;
 
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.util.List;
 
 import org.apache.maven.artifact.Artifact;
@@ -48,7 +47,7 @@ public interface ArtifactRepository {
     String getBasedir();
 
     default Path getBasedirPath() {
-        return Paths.get(getBasedir());
+        return Path.of(getBasedir());
     }
 
     String getProtocol();

compat/maven-artifact/src/main/java/org/apache/maven/artifact/versioning/ComparableVersion.java

@@ -543,7 +543,7 @@ void normalize() {
                     if (i == size() - 1 || get(i + 1).getType() == STRING_ITEM) {
                         remove(i);
                     } else if (get(i + 1).getType() == LIST_ITEM) {
-                        Item item = ((ListItem) get(i + 1)).get(0);
+                        Item item = ((ListItem) get(i + 1)).getFirst();
                         if (item.getType() == COMBINATION_ITEM || item.getType() == STRING_ITEM) {
                             remove(i);
                         }

compat/maven-artifact/src/test/java/org/apache/maven/artifact/versioning/ComparableVersionIT.java

@@ -23,7 +23,6 @@
 import java.nio.file.FileVisitResult;
 import java.nio.file.Files;
 import java.nio.file.Path;
-import java.nio.file.Paths;
 import java.nio.file.SimpleFileVisitor;
 import java.nio.file.attribute.BasicFileAttributes;
 import java.util.regex.Pattern;
@@ -36,15 +35,15 @@ class ComparableVersionIT {
 
     @Test
     void test() throws Exception {
-        Files.walkFileTree(Paths.get("target"), new SimpleFileVisitor<Path>() {
+        Files.walkFileTree(Path.of("target"), new SimpleFileVisitor<Path>() {
             Pattern mavenArtifactJar = Pattern.compile("maven-artifact-[\\d.]+(-SNAPSHOT)?\\.jar");
 
             @Override
             public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IOException {
                 String filename = file.getFileName().toString();
                 if (mavenArtifactJar.matcher(filename).matches()) {
                     Process p = Runtime.getRuntime().exec(new String[] {
-                        Paths.get(System.getProperty("java.home"), "bin/java").toString(),
+                        Path.of(System.getProperty("java.home"), "bin/java").toString(),
                         "-jar",
                         file.toAbsolutePath().toString(),
                         "5.32",
@@ -64,7 +63,7 @@ public FileVisitResult visitFile(Path file, BasicFileAttributes attrs) throws IO
 
             @Override
             public FileVisitResult preVisitDirectory(Path dir, BasicFileAttributes attrs) throws IOException {
-                if (Paths.get("target").equals(dir)) {
+                if (Path.of("target").equals(dir)) {
                     return FileVisitResult.CONTINUE;
                 } else {
                     return FileVisitResult.SKIP_SUBTREE;

compat/maven-artifact/src/test/java/org/apache/maven/artifact/versioning/ComparableVersionTest.java

@@ -437,7 +437,7 @@ void testMng6964() {
     @Test
     void testLocaleIndependent() {
         Locale orig = Locale.getDefault();
-        Locale[] locales = {Locale.ENGLISH, new Locale("tr"), Locale.getDefault()};
+        Locale[] locales = {Locale.ENGLISH, Locale.of("tr"), Locale.getDefault()};
         try {
             for (Locale locale : locales) {
                 Locale.setDefault(locale);