Migrate from Maven Archiver to standard jar tool by using the standard java.util.spi.ToolProvider API (requires Java 9+).

Files in the `classes` directories are dispatched to the `--manifest` and `--release` options, which allow additional verifications by the `jar` tool.
Derive a POM for each individual JAR file as the intersection of the project model and the module-info of the JAR file.

Side effects:
* Remove the default `**/package.html` exclude.
* Automatic use of `META-INF/MANIFEST.MF` file found in `classes` directory.
* Automatic Multi-Release always enabled, unless `detectMultiReleaseJar` is set to `false`.
* In a multi-module project, use Java module names as artifact names.
* Whether the `--date` option is supported depends on the Java version.
* Re-run the `jar` tool with the --validate operation mode if validation was not implicit.

Author: desruisseaux

pom.xml

@@ -34,6 +34,26 @@
   <name>Apache Maven JAR Plugin</name>
   <description>Builds a Java Archive (JAR) file from the compiled project classes and resources.</description>
 
+  <developers>
+    <developer>
+      <id>evenisse</id>
+      <name>Emmanuel Venisse</name>
+      <email>evenisse@apache.org</email>
+      <roles>
+        <role>Java Developer</role>
+      </roles>
+    </developer>
+    <developer>
+      <id>desruisseaux</id>
+      <name>Martin Desruisseaux</name>
+      <email>desruisseaux@apache.org</email>
+      <organization>Geomatys</organization>
+      <roles>
+        <role>Java Developer</role>
+      </roles>
+      <timezone>+1</timezone>
+    </developer>
+  </developers>
   <contributors>
     <contributor>
       <name>Jerome Lacoste</name>
@@ -132,6 +152,12 @@
       <version>${mavenVersion}</version>
       <scope>provided</scope>
     </dependency>
+    <dependency>
+      <groupId>org.apache.maven</groupId>
+      <artifactId>maven-support</artifactId>
+      <version>${mavenVersion}</version>
+      <scope>compile</scope>
+    </dependency>
     <dependency>
       <groupId>org.apache.maven</groupId>
       <artifactId>maven-api-xml</artifactId>
@@ -209,7 +235,7 @@
               <!--
                 ! The manifest specification does not describe any method for writing comments into the manifest.
               -->
-              <exclude>src/it/mjar-71-01/src/main/resources/META-INF/MANIFEST.MF</exclude>
+              <exclude>src/it/mjar-71-01/src/main/my-custom-dir/some-manifest.mf</exclude>
               <exclude>src/it/mjar-71-02/src/main/resources/META-INF/MANIFEST.MF</exclude>
             </excludes>
           </configuration>

src/it/MJAR-260-invalid-automatic-module-name/verify.bsh

@@ -45,8 +45,7 @@ try
     String[] snippets = new String[] {
       "[INFO] BUILD FAILURE",
       "[ERROR] Failed to execute goal org.apache.maven.plugins:maven-jar-plugin",
-      "Caused by: org.apache.maven.api.plugin.MojoException: Error while assembling the JAR file.",
-      "Caused by: org.codehaus.plexus.archiver.jar.ManifestException: Invalid automatic module name: 'in-valid.name.with.new.keyword'"
+      "Caused by: org.apache.maven.api.plugin.MojoException: Invalid automatic module name: \"in-valid.name.with.new.keyword\"."
     };
 
     System.out.println("\nVerifying log snippets...");

src/it/MJAR-275-reproducible-module-info/invoker.properties

@@ -5,17 +5,15 @@
 # to you under the Apache License, Version 2.0 (the
 # "License"); you may not use this file except in compliance
 # with the License.  You may obtain a copy of the License at
-# 
+#
 #   http://www.apache.org/licenses/LICENSE-2.0
-# 
+#
 # Unless required by applicable law or agreed to in writing,
 # software distributed under the License is distributed on an
 # "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 # KIND, either express or implied.  See the License for the
 # specific language governing permissions and limitations
 # under the License.
 
-# NOTE: Requires Java 10+ to compile the module declaration for Java 9+,
-# this is due that compiling the module declaration generates a
-# module descriptor with the JDK version on it, making it unreproducible.
-invoker.java.version = 10+
+# The --date option needed for reproducible build is available only since Java 19.
+invoker.java.version = 19+

src/it/MJAR-292-detect-mjar/pom.xml

@@ -86,8 +86,8 @@
             </manifest>
             <manifestEntries>
               <!--
-                We override this config since we are detecting the versioned area,
-                The output JAR should contain `Multi-Release: true`
+                For verifying that this entry will be overridden.
+                If users really want to disable multi-release, they should set <detectMultiReleaseJar> to false.
                -->
               <Multi-Release>false</Multi-Release>
             </manifestEntries>

src/it/MJAR-292-disable-detect-mjar/pom.xml

@@ -84,6 +84,7 @@
               <mainClass>myproject.HelloWorld</mainClass>
             </manifest>
           </archive>
+          <detectMultiReleaseJar>false</detectMultiReleaseJar>
         </configuration>
       </plugin>
     </plugins>

src/it/MJAR-30-include/verify.groovy

@@ -67,7 +67,7 @@ try
     {
         String artifactName = artifactNames[i];
 		if ( !contents.contains( artifactName ) )
-		{
+        {
         	System.err.println( "Artifact[" + artifactName + "] not found in jar archive" );
         	return false;
         }

src/it/MJAR-70-recreation/verify.bsh

@@ -58,7 +58,7 @@ if ( buildLog.exists() ) {
 int jarPluginExecutions = 0;
 String[] lines = buildLogContent.split( "\n" );
 for ( String line : lines ) {
-    if ( line.contains( "Building jar:" ) && line.contains( "MJAR-70-recreation-1.0-SNAPSHOT.jar" ) ) {
+    if ( line.contains( "Building JAR:" ) && line.contains( "MJAR-70-recreation-1.0-SNAPSHOT.jar" ) ) {
         jarPluginExecutions++;
         System.out.println( "Found JAR creation: " + line );
     }

src/it/mjar-71-01/pom.xml

@@ -25,7 +25,7 @@ under the License.
   <version>1.0</version>
   <packaging>jar</packaging>
   <name>it-mjar-71</name>
-  <description>Test that the default manifest is added by default if found under target/classes. Can also be overriden.</description>
+  <description>Test that the specified manifest is used.</description>
   <url>http://maven.apache.org</url>
 
   <build>
@@ -36,7 +36,7 @@ under the License.
         <version>@project.version@</version>
         <configuration>
           <archive>
-            <manifestFile>src/main/resources/META-INF/MANIFEST.MF</manifestFile>
+            <manifestFile>src/main/my-custom-dir/some-manifest.mf</manifestFile>
           </archive>
         </configuration>
       </plugin>

…/src/main/resources/META-INF/MANIFEST.MF …/src/main/my-custom-dir/some-manifest.mfsrc/it/mjar-71-01/src/main/resources/META-INF/MANIFEST.MF renamed to src/it/mjar-71-01/src/main/my-custom-dir/some-manifest.mf src/it/mjar-71-01/src/main/resources/META-INF/MANIFEST.MF renamed to src/it/mjar-71-01/src/main/my-custom-dir/some-manifest.mf

@@ -51,14 +51,14 @@ try
             // Only compare files
             if ( entry.getName().equals( "META-INF/MANIFEST.MF" ) )
             {
-            	String manifest = IOUtils.toString( jar.getInputStream ( entry ) );
-            	int index = manifest.indexOf( "Archiver-Version: foobar-1.23456" );
-            	if ( index <= 0 )
-            	{	
-            		System.err.println( "MANIFEST doesn't contain: 'Archiver-Version: foobar-1.23456'" );
-            		return false;
-            	}
-            	return true;
+                String manifest = IOUtils.toString( jar.getInputStream ( entry ) );
+                int index = manifest.indexOf( "Archiver-Version: foobar-1.23456" );
+                if ( index <= 0 )
+                {
+                    System.err.println( "MANIFEST doesn't contain: 'Archiver-Version: foobar-1.23456'" );
+                    return false;
+                }
+                return true;
             }
         }
     }