fix build warnings and revert compiler workaround

demo/osgi-repository/my-bundle/pom.xml

@@ -7,8 +7,8 @@
 	</parent>
 	<artifactId>my-bundle</artifactId>
 	<properties>
-		<maven.compiler.source>1.8</maven.compiler.source>
-		<maven.compiler.target>1.8</maven.compiler.target>
+		<maven.compiler.source>8</maven.compiler.source>
+		<maven.compiler.target>8</maven.compiler.target>
 	</properties>
 	<dependencies>
 		<dependency>

pom.xml

@@ -395,8 +395,6 @@
 					<configuration>
 						<source>${min.jdk.version}</source>
 						<target>${min.jdk.version}</target>
-						<!-- Workaround for https://issues.apache.org/jira/browse/MCOMPILER-567 -->
-						<useIncrementalCompilation>false</useIncrementalCompilation>
 					</configuration>
 				</plugin>
 				<plugin>
@@ -635,6 +633,28 @@
 				</plugins>
 			</build>
 		</profile>
+        <profile>
+            <!-- allow annotation processing on JDK 21+ -->
+            <id>avoid-maven-compiler-warnings</id>
+            <activation>
+                <jdk>[21,)</jdk>
+            </activation>
+            <build>
+				<pluginManagement>
+					<plugins>
+						<plugin>
+							<groupId>org.apache.maven.plugins</groupId>
+							<artifactId>maven-compiler-plugin</artifactId>
+							<configuration>
+								<!-- avoid annotation processor warning on JDK 21+.
+								The flag must be set explicitly there. -->
+								<proc>full</proc>
+							</configuration>
+						</plugin>
+					</plugins>
+				</pluginManagement>
+			</build>
+        </profile>
 	</profiles>
 	<distributionManagement>
 		<site>

tycho-compiler-plugin/src/main/java/copied/org/apache/maven/plugin/AbstractCompilerMojo.java

@@ -49,7 +49,7 @@
  * TODO: At least one step could be optimized, currently the plugin will do two scans of all the
  * source code if the compiler has to have the entire set of sources. This is currently the case for
  * at least the C# compiler and most likely all the other .NET compilers too.
- * 
+ *
  * @author others
  * @author <a href="mailto:trygvis@inamo.no">Trygve Laugst&oslash;l</a>
  * @author Jan Sievers (SAP) added support for annotation processor options
@@ -124,9 +124,10 @@ public abstract class AbstractCompilerMojo extends AbstractMojo {
 
     /**
      * The -encoding argument for the Java compiler (kept for backwards compatibility)
-     * 
+     *
      * @deprecated use {@link #encoding}
      */
+    @Deprecated
     @Parameter(property = "maven.compiler.encoding", readonly = true)
     private String mavenCompilerEncoding;
 
@@ -183,13 +184,13 @@ public abstract class AbstractCompilerMojo extends AbstractMojo {
     private String executable;
 
     /**
-     * If <code>only</code> is specified, the annotation processors will run but no compilation will be
-     * performed. If <code>none</code> is specified, annotation processors will not be discovered or
-     * run; compilation will proceed as if no annotation processors were found. By default the
-     * compiler must search the classpath for annotation processors, so specifying <code>none</code> may
-     * speed compilation if annotation processing is not required. This parameter requires a 1.6 VM
-     * or above and is used only if the compliance is 1.6
-     * 
+     * If <code>only</code> is specified, the annotation processors will run but no compilation will
+     * be performed. If <code>none</code> is specified, annotation processors will not be discovered
+     * or run; compilation will proceed as if no annotation processors were found. By default the
+     * compiler must search the classpath for annotation processors, so specifying <code>none</code>
+     * may speed compilation if annotation processing is not required. This parameter requires a 1.6
+     * VM or above and is used only if the compliance is 1.6
+     *
      * @since 0.16.0
      */
     @Parameter
@@ -200,7 +201,7 @@ public abstract class AbstractCompilerMojo extends AbstractMojo {
      * <a href="https://java.sun.com/javase/6/docs/api/javax/annotation/processing/Processor.html" >
      * normal processor discovery process</a> will be skipped. This parameter requires a 1.6 VM or
      * above and is used only if the compliance is 1.6
-     * 
+     *
      * @since 0.16.0
      */
     @Parameter
@@ -209,7 +210,7 @@ public abstract class AbstractCompilerMojo extends AbstractMojo {
     /**
      * The directory where source files generated by annotation processors will be created. This
      * parameter requires a 1.6 VM or above and is used only if the compliance is 1.6.
-     * 
+     *
      * @since 0.16.0
      */
     @Parameter(defaultValue = "${project.build.directory}/generated-sources/annotations")
@@ -223,15 +224,16 @@ public abstract class AbstractCompilerMojo extends AbstractMojo {
      * This is because the list of valid arguments passed to a Java compiler varies based on the
      * compiler version.
      * </p>
-     * 
+     *
      * @deprecated use {@link #compilerArgs} instead.
      */
+    @Deprecated
     @Parameter
     private Map<String, String> compilerArguments;
 
     /**
      * Arguments to be passed to the compiler.
-     * 
+     *
      * @since 0.17.0
      */
     @Parameter

tycho-extras/tycho-p2-extras-plugin/src/main/java/org/eclipse/tycho/plugins/p2/extras/MirrorMojo.java

@@ -66,8 +66,8 @@ public class MirrorMojo extends AbstractMojo {
 
     /**
      * Source repositori(es) to mirror from.
-     * 
-     * @see {@link #targetPlatformAsSource} and {@link #currentModuleAsSource}
+     *
+     * See also {@link #targetPlatformAsSource} and {@link #currentModuleAsSource}
      */
     @Parameter(required = false)
     private List<Repository> source;
@@ -166,7 +166,7 @@ public class MirrorMojo extends AbstractMojo {
      * Add XZ-compressed repository index files. XZ offers better compression ratios esp. for highly
      * redundant file content.
      * </p>
-     * 
+     *
      * @since 0.25.0
      */
     @Parameter(defaultValue = "true")
@@ -178,7 +178,7 @@ public class MirrorMojo extends AbstractMojo {
      * addition to XZ-compressed index files. This fallback provides backwards compatibility for
      * pre-Mars p2 clients which cannot read XZ-compressed index files.
      * </p>
-     * 
+     *
      * @since 0.25.0
      */
     @Parameter(defaultValue = "true")
@@ -189,7 +189,7 @@ public class MirrorMojo extends AbstractMojo {
      * Whether to add the target-platform content as a source. Ignored for non-Tycho packaging
      * types.
      * </p>
-     * 
+     *
      * @since 1.1.0
      */
     @Parameter(defaultValue = "false")
@@ -200,7 +200,7 @@ public class MirrorMojo extends AbstractMojo {
      * Whether the current build p2 output should be added as source. Ignored for non-Tycho
      * packaging types. Ignored if {@link #targetPlatformAsSource} == false;
      * </p>
-     * 
+     *
      * @since 1.1.0
      */
     @Parameter(defaultValue = "true")
@@ -211,7 +211,7 @@ public class MirrorMojo extends AbstractMojo {
      * If set to true, mirroring continues to run in the event of an error during the mirroring
      * process and will just log an info message.
      * </p>
-     * 
+     *
      * @since 1.1.0
      */
     @Parameter(defaultValue = "false")

tycho-extras/tycho-p2-extras-plugin/src/main/java/org/eclipse/tycho/plugins/p2/extras/PublishFeaturesAndBundlesMojo.java

@@ -31,8 +31,8 @@
 
 /**
  * This goal invokes the feature and bundle publisher on a folder.
- * 
- * @see https://wiki.eclipse.org/Equinox/p2/Publisher#Features_And_Bundles_Publisher_Application
+ *
+ * @see <a href="https://wiki.eclipse.org/Equinox/p2/Publisher#Features_And_Bundles_Publisher_Application">Eclipse Wiki</a>
  */
 @Mojo(name = "publish-features-and-bundles", threadSafe = true)
 public class PublishFeaturesAndBundlesMojo extends AbstractMojo {
@@ -49,7 +49,7 @@ public class PublishFeaturesAndBundlesMojo extends AbstractMojo {
      * Location of the artifact repository to write. Note: The AssembleRepositoryMojo of
      * tycho-p2-repository-plugin will only work with the predefined default
      * ${project.build.directory}/repository.
-     * 
+     *
      */
     @Parameter(defaultValue = "${project.build.directory}/repository")
     private String artifactRepositoryLocation;

tycho-its/projects/TYCHO590annotationProcessing/annotated-project/pom.xml

@@ -3,22 +3,22 @@
 	<modelVersion>4.0.0</modelVersion>
 	<groupId>org.eclipse.tycho.tychoits.TYCHO590</groupId>
 	<artifactId>annotated-project</artifactId>
-	
+
 	<parent>
 		<groupId>org.eclipse.tycho.tychoits.TYCHO590</groupId>
 		<artifactId>parent</artifactId>
 		<version>1.0.0-SNAPSHOT</version>
 	</parent>
-	
+
 	<build>
 		<plugins>
 			<plugin>
 				<groupId>org.apache.maven.plugins</groupId>
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>3.10.1</version>
 				<configuration>
-					<source>1.8</source>
-					<target>1.8</target>
+					<source>8</source>
+					<target>8</target>
 					<fork>false</fork>
 					<compilerId>jdt</compilerId>
 					<annotationProcessors>

tycho-its/projects/TYCHO590annotationProcessing/pom.xml

@@ -5,7 +5,7 @@
 	<artifactId>parent</artifactId>
 	<version>1.0.0-SNAPSHOT</version>
 	<packaging>pom</packaging>
-	
+
 	<modules>
 		<module>annotation-processor</module>
 		<module>annotated-project</module>
@@ -18,8 +18,8 @@
 				<artifactId>maven-compiler-plugin</artifactId>
 				<version>3.10.1</version>
 				<configuration>
-					<source>1.8</source>
-					<target>1.8</target>
+					<source>8</source>
+					<target>8</target>
 					<fork>false</fork>
 					<compilerId>jdt</compilerId>
 				</configuration>

tycho-its/projects/document-bundle-plugin/test1/doclet/pom.xml

@@ -12,12 +12,12 @@
 	<packaging>jar</packaging>
 
 	<properties>
-		<maven.compiler.target>1.8</maven.compiler.target>
-		<maven.compiler.source>1.8</maven.compiler.source>
+		<maven.compiler.target>8</maven.compiler.target>
+		<maven.compiler.source>8</maven.compiler.source>
 	</properties>
-	
+
 	<dependencies>
-		<!-- Adding another dependency just to verify that also transitive dependencies 
+		<!-- Adding another dependency just to verify that also transitive dependencies
 		get resolved and added to the javadoc execution class path  -->
 		<dependency>
 			<groupId>org.eclipse.tycho</groupId>

tycho-lib-detector/pom.xml

@@ -26,7 +26,7 @@
 				<plugin>
 					<groupId>org.apache.maven.plugins</groupId>
 					<artifactId>maven-compiler-plugin</artifactId>
-					<configuration>
+					<configuration combine.self="override">
 						<!-- make sure we use minimum source/target level as this code will be run in old JVMs -->
 						<source>1.3</source>
 						<target>1.1</target>

tycho-p2-publisher-plugin/src/main/java/org/eclipse/tycho/plugins/p2/publisher/PublishCategoriesMojo.java

@@ -42,7 +42,7 @@
  * Publishes the category definitions from the <code>category.xml</code> in the root of the project.
  * </p>
  *
- * @see https://wiki.eclipse.org/Equinox/p2/Publisher
+ * @see <a href="https://wiki.eclipse.org/Equinox/p2/Publisher">Eclipse Wiki</a>
  */
 @Mojo(name = "publish-categories", defaultPhase = LifecyclePhase.PACKAGE, threadSafe = true, requiresDependencyResolution = ResolutionScope.COMPILE_PLUS_RUNTIME)
 public final class PublishCategoriesMojo extends AbstractPublishMojo {
@@ -80,7 +80,7 @@ protected Collection<DependencySeed> publishContent(PublisherServiceFactory publ
 
     /**
      * Writes the Tycho-internal representation of categories back to a category.xml.
-     * 
+     *
      * @param category
      *            a category, with "qualifier" literals already replaced by the build qualifier.
      */

tycho-p2-publisher-plugin/src/main/java/org/eclipse/tycho/plugins/p2/publisher/PublishProductMojo.java

@@ -70,8 +70,8 @@
  * Publishes all product definitions files (<code>*.product</code>) that are present in the root of
  * the project.
  * </p>
- * 
- * @see https://wiki.eclipse.org/Equinox/p2/Publisher
+ *
+ * @see <a href="https://wiki.eclipse.org/Equinox/p2/Publisher">Eclipse Wiki</a>
  */
 @Mojo(name = "publish-products", defaultPhase = LifecyclePhase.PACKAGE, threadSafe = true, requiresDependencyResolution = ResolutionScope.COMPILE_PLUS_RUNTIME)
 public final class PublishProductMojo extends AbstractPublishMojo {

tycho-surefire/org.eclipse.tycho.bnd.executionlistener/pom.xml

@@ -7,7 +7,7 @@
 	</parent>
 	<artifactId>org.eclipse.tycho.bnd.executionlistener</artifactId>
 	<properties>
-		<min.jdk.version>1.8</min.jdk.version>
+		<min.jdk.version>8</min.jdk.version>
 	</properties>
 	<dependencies>
 		<dependency>

tycho-surefire/org.eclipse.tycho.surefire.osgibooter/pom.xml

@@ -21,7 +21,7 @@
 	<packaging>jar</packaging>
 	<name>Tycho Surefire OSGi Booter Eclipse Application</name>
 	<properties>
-		<java.version>1.8</java.version>
+		<java.version>8</java.version>
 		<maven.compiler.source>${java.version}</maven.compiler.source>
 		<maven.compiler.target>${java.version}</maven.compiler.target>
 	</properties>