removed extraclasspath manifest attribute when Gradle task property is empty

LICENSE.md

@@ -0,0 +1,22 @@
+Copyright 2023 Walter Oggioni
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.

README.md

@@ -0,0 +1,113 @@
+## Overview
+Envelope is a simple Gradle plugin that allows you to create an executable jar file
+that includes all runtime dependencies and can be executed with a simple
+
+```bash
+java -jar my-app.jar
+```
+It supports JPMS, embedded system properties, Java agents, extra folders to be added to classpath. 
+
+### Usage
+
+Declare the plugin in your build's `settings.gradle` like this
+```groovy
+
+pluginManagement {
+    repositories {
+        maven {
+            url = 'https://woggioni.net/mvn/'
+        }
+    }
+
+    plugins {
+        id "net.woggioni.gradle.envelope" version "2023.09.25"
+    }
+}
+```
+
+Then add it to a project's `build.gradle`
+
+```groovy
+plugins {
+    id 'net.woggioni.gradle.envelope'
+}
+
+envelopeJar {
+    mainClass = 'your.main.Class'
+}
+```
+
+The plugin adds 2 tasks to your project:
+
+- `envelopeJar` of type `net.woggioni.gradle.envelope.EnvelopeJarTask` that creates the executable jar in the project's libraries folder
+- `envelopeRun` of type `org.gradle.api.tasks.JavaExec` which launches the jar created by the `envelopeJar` task
+
+### Configuration
+
+`EnvelopeJarTask` has several properties useful for configuration purposes:
+
+###### mainClass 
+
+This string property sets the class that will be searched for the `main` method to start the application
+
+###### mainModule
+
+When this string property is set, the jar file will be started in JPMS mode (if running on Java 9+) and 
+this module will be searched for the main class, if the `mainClass` is not set the main class specified 
+in the module descriptor will be loaded instead
+
+###### systemProperties
+
+This is a map that contains Java system properties that will be set before your application starts
+
+###### extraClasspath
+
+This is a list of strings representing filesystem paths that will be added to the classpath (if running in classpath mode) 
+or to the module path (if running in JPMS mode) when the application starts. 
+
+Relative paths and interpolation with Java System properties and environmental variables are supported:
+
+e.g.
+
+This looks for a `plugin` folder in the user's home directory
+```
+${env:HOME}/plugins
+```
+
+Same using Java system properties instead
+```
+${sys:user.home}/plugins
+```
+
+###### javaAgent
+This is a method accepting 2 strings, the first is the Java agent classname and the second one is the java agent arguments.
+It can be invoked multiple times to setup multiple java agents for the same JAR file. 
+All the java agents will be invoked before the application startup.
+
+### Example
+
+```groovy
+plugins {
+    id 'net.woggioni.gradle.envelope'
+}
+
+envelopeJar {
+    mainClass = 'your.main.Class'
+    mainModule = 'your.main.module'
+
+    systemProperties = [
+        'some.property' : 'Some value'
+    ]
+
+    extraClasspath = ["plugins"]
+    
+    javaAgent('your.java.agent.Class', 'optional agent arguments')
+}
+```
+
+### Limitations
+
+This plugin requires Gradle >= 6.0 and Java >=0 8 to build the executable jar file.
+The assembled envelope jar requires and Java >= 8 to run, if only `mainClass` is specified,
+if both `mainModule` and `mainClass` are specified the generated jar file will (try to) run in classpath mode on Java 8
+and in JPMS mode on Java > 8.

common/src/main/java/net/woggioni/envelope/Common.java

@@ -1,24 +1,27 @@
 package net.woggioni.envelope;
 
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+import lombok.SneakyThrows;
+
 import java.io.BufferedInputStream;
 import java.io.BufferedOutputStream;
 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileOutputStream;
+import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
 import java.security.DigestInputStream;
 import java.security.MessageDigest;
 import java.util.AbstractMap;
 import java.util.Map;
+import java.util.MissingFormatArgumentException;
 import java.util.Optional;
 import java.util.function.Supplier;
+import java.util.stream.Stream;
 import java.util.zip.CRC32;
 import java.util.zip.ZipEntry;
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
-import lombok.SneakyThrows;
-import java.io.IOException;
 
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class Common {
@@ -114,4 +117,152 @@ public class Common {
         OutputStream result = new FileOutputStream(file);
         return buffered ? new BufferedOutputStream(result) : result;
     }
+
+    /**
+     * @param template  Template text containing the variables to be replaced by this method. <br>
+     *                  Variables follow the format ${variable_name}. <br>
+     *                  Example: <br>
+     *                  "This template was created by ${author}."
+     * @param valuesMap A hashmap with the values of the variables to be replaced. <br>
+     *                  The key is the variable name and the value is the value to be replaced in the template. <br>
+     *                  Example: <br>
+     *                  {"author" =&gt; "John Doe"}
+     * @return The template text (String) with the variable names replaced by the values passed in the map. <br>
+     * If any of the variable names is not contained in the map it will be replaced by an empty string. <br>
+     * Example: <br>
+     * "This template was created by John Doe."
+     */
+    public static String renderTemplate(String template, Map<String, Object> valuesMap) {
+        return renderTemplate(template, valuesMap, null);
+    }
+
+
+    public static int indexOfWithEscape(String haystack, char needle, char escape, int begin, int end) {
+        int result = -1;
+        int cursor = begin;
+        if (end == 0) {
+            end = haystack.length();
+        }
+        int escapeCount = 0;
+        while (cursor < end) {
+            char c = haystack.charAt(cursor);
+            if (escapeCount > 0) {
+                --escapeCount;
+                if (c == escape) {
+                    result = -1;
+                }
+            } else if (escapeCount == 0) {
+                if (c == escape) {
+                    ++escapeCount;
+                }
+                if (c == needle) {
+                    result = cursor;
+                }
+            }
+            if (result >= 0 && escapeCount == 0) {
+                break;
+            }
+            ++cursor;
+        }
+        return result;
+    }
+
+    public static String renderTemplate(
+        String template,
+        Map<String, Object> valuesMap,
+        Map<String, Map<String, Object>> dictMap) {
+        StringBuilder sb = new StringBuilder();
+        Object absent = new Object();
+        int cursor = 0;
+        TokenScanner tokenScanner = new TokenScanner(template, '$', '$');
+        while (cursor < template.length()) {
+            tokenScanner.next();
+            int nextPlaceHolder;
+            switch (tokenScanner.getTokenType()) {
+                case TOKEN: {
+                    nextPlaceHolder = tokenScanner.getTokenIndex();
+                    while (cursor < nextPlaceHolder) {
+                        char ch = template.charAt(cursor++);
+                        sb.append(ch);
+                    }
+                    if (cursor + 1 < template.length() && template.charAt(cursor + 1) == '{') {
+                        String key;
+                        String context = null;
+                        String defaultValue = null;
+                        Object value;
+                        int end = template.indexOf('}', cursor + 1);
+                        int colon;
+                        if (dictMap == null)
+                            colon = -1;
+                        else {
+                            colon = indexOfWithEscape(template, ':', '\\', cursor + 1, template.length());
+                            if (colon >= end) colon = -1;
+                        }
+                        if (colon < 0) {
+                            key = template.substring(cursor + 2, end);
+                            value = valuesMap.getOrDefault(key, absent);
+                        } else {
+                            context = template.substring(cursor + 2, colon);
+                            int secondColon = indexOfWithEscape(template, ':', '\\', colon + 1, end);
+                            if (secondColon < 0) {
+                                key = template.substring(colon + 1, end);
+                            } else {
+                                key = template.substring(colon + 1, secondColon);
+                                defaultValue = template.substring(secondColon + 1, end);
+                            }
+                            value = Optional.ofNullable(dictMap.get(context))
+                                .map(m -> m.get(key))
+                                .orElse(absent);
+                        }
+                        if (value != absent) {
+                            sb.append(value.toString());
+                        } else {
+                            if (defaultValue != null) {
+                                sb.append(defaultValue);
+                            } else {
+                                throw new MissingFormatArgumentException(
+                                    String.format("Missing value for placeholder '%s'",
+                                        context == null ? key : context + ':' + key
+                                    )
+                                );
+                            }
+                        }
+                        cursor = end + 1;
+                    }
+                    break;
+                }
+                case ESCAPE:
+                    nextPlaceHolder = tokenScanner.getTokenIndex();
+                    while (cursor < nextPlaceHolder) {
+                        char ch = template.charAt(cursor++);
+                        sb.append(ch);
+                    }
+                    cursor = nextPlaceHolder + 1;
+                    sb.append(template.charAt(cursor++));
+                    break;
+                case END:
+                default:
+                    nextPlaceHolder = template.length();
+                    while (cursor < nextPlaceHolder) {
+                        char ch = template.charAt(cursor++);
+                        sb.append(ch);
+                    }
+                    break;
+            }
+        }
+        return sb.toString();
+    }
+
+    public static <T> Stream<T> opt2Stream(Optional<T> opt) {
+        return opt.map(Stream::of).orElse(Stream.empty());
+    }
+
+    public static <T> Optional<T> or(Supplier<T> ...suppliers) {
+        Optional<T> result = Optional.empty();
+        for(Supplier<T> supplier : suppliers) {
+            T value = supplier.get();
+            if(value != null) return Optional.of(value);
+        }
+        return result;
+    }
 }

common/src/main/java/net/woggioni/envelope/Constants.java

@@ -1,9 +1,10 @@
 package net.woggioni.envelope;
 
+import lombok.AccessLevel;
+import lombok.NoArgsConstructor;
+
 import java.util.Calendar;
 import java.util.GregorianCalendar;
-import lombok.AccessLevel;
-import lombok.NoArgsConstructor;
 
 @NoArgsConstructor(access = AccessLevel.PRIVATE)
 public class Constants {
@@ -16,13 +17,22 @@ public class Constants {
     public static final String SYSTEM_PROPERTIES_FILE = METADATA_FOLDER + "/system.properties";
 
     public static final String LIBRARIES_TOC = METADATA_FOLDER + "/libraries.txt";
+    public static final char EXTRA_CLASSPATH_ENTRY_SEPARATOR = ';';
 
     public static class ManifestAttributes {
         public static final String MAIN_MODULE = "Executable-Jar-Main-Module";
         public static final String MAIN_CLASS = "Executable-Jar-Main-Class";
+        public static final String EXTRA_CLASSPATH = "Executable-Jar-Extra-Classpath";
         public static final String ENTRY_HASH = "SHA-256-Digest";
     }
 
+    public static class JvmProperties {
+        private static final String PREFIX = "envelope.";
+        public static final String MAIN_MODULE = PREFIX + "main.module";
+        public static final String MAIN_CLASS = PREFIX + "main.class";
+        public static final String EXTRA_CLASSPATH = PREFIX + "extra.classpath";
+    }
+
     /**
      * This value is used as a default file timestamp for all the zip entries when
      * <a href="https://docs.gradle.org/current/javadoc/org/gradle/api/tasks/bundling/AbstractArchiveTask.html#isPreserveFileTimestamps--">AbstractArchiveTask.isPreserveFileTimestamps</a>

common/src/main/java/net/woggioni/envelope/TokenScanner.java

@@ -0,0 +1,74 @@
+package net.woggioni.envelope;
+
+import lombok.Getter;
+
+public class TokenScanner {
+
+    public enum TokenType {
+        ESCAPE, TOKEN, END;
+    }
+    private final String haystack;
+    private final char needle;
+    private final char escape;
+    private int begin;
+    private final int end;
+
+    @Getter
+    private int tokenIndex = -1;
+
+    @Getter
+    private TokenType tokenType = null;
+
+    public TokenScanner(String haystack, char needle, char escape, int begin, int end) {
+        this.haystack = haystack;
+        this.needle = needle;
+        this.escape = escape;
+        this.begin = begin;
+        this.end = end;
+    }
+
+    public TokenScanner(String haystack, char needle, char escape, int begin) {
+        this(haystack, needle, escape, begin, haystack.length());
+    }
+
+    public TokenScanner(String haystack, char needle, char escape) {
+        this(haystack, needle, escape, 0, haystack.length());
+    }
+
+    public void next() {
+        int result = -1;
+        int cursor = begin;
+        int escapeCount = 0;
+        while(true) {
+            if(cursor < end) {
+                char c = haystack.charAt(cursor);
+                if (escapeCount > 0) {
+                    --escapeCount;
+                    if(c == escape || c == needle) {
+                        tokenIndex = cursor - 1;
+                        tokenType = TokenType.ESCAPE;
+                        break;
+                    }
+                } else if (escapeCount == 0) {
+                    if (c == escape) {
+                        ++escapeCount;
+                    }
+                    if (c == needle) {
+                        result = cursor;
+                    }
+                }
+                if (result >= 0 && escapeCount == 0) {
+                    tokenIndex = result;
+                    tokenType = TokenType.TOKEN;
+                    break;
+                }
+                ++cursor;
+            } else {
+                tokenIndex = result;
+                tokenType = result < 0 ? TokenType.END :TokenType.TOKEN;
+                break;
+            }
+        }
+        begin = cursor + 1;
+    }
+}

gradle.properties

@@ -1,7 +1,7 @@
 woggioniMavenRepositoryUrl=https://woggioni.net/mvn/
 publishMavenRepositoryUrl=https://mvn.woggioni.net/
 
-lys.version = 0.2-SNAPSHOT
+lys.version = 2024.02.24
 
-version.envelope=2023.03
+version.envelope=2024.02.28
 version.gradle=7.6

gradle/wrapper/gradle-wrapper.properties

@@ -1,5 +1,6 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionUrl=https\://services.gradle.org/distributions/gradle-7.6-all.zip
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.3-bin.zip
+networkTimeout=10000
 zipStoreBase=GRADLE_USER_HOME
 zipStorePath=wrapper/dists

gradlew

@@ -55,7 +55,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -80,10 +80,10 @@ do
     esac
 done
 
-APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
-
-APP_NAME="Gradle"
+# This is normally unused
+# shellcheck disable=SC2034
 APP_BASE_NAME=${0##*/}
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
 
 # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
 DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
@@ -143,12 +143,16 @@ fi
 if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
     case $MAX_FD in #(
       max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045 
         MAX_FD=$( ulimit -H -n ) ||
             warn "Could not query maximum file descriptor limit"
     esac
     case $MAX_FD in  #(
       '' | soft) :;; #(
       *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC3045 
         ulimit -n "$MAX_FD" ||
             warn "Could not set maximum file descriptor limit to $MAX_FD"
     esac

gradlew.bat

@@ -26,6 +26,7 @@ if "%OS%"=="Windows_NT" setlocal
 
 set DIRNAME=%~dp0
 if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
 set APP_BASE_NAME=%~n0
 set APP_HOME=%DIRNAME%
 

launcher/build.gradle

@@ -7,12 +7,15 @@ ext {
     setProperty('jpms.module.name', 'net.woggioni.envelope')
 }
 
+
 configurations {
     embedded {
         visible = false
         canBeConsumed = false
     }
-    compileOnly.extendsFrom(embedded)
+    compileOnly {
+        extendsFrom(embedded)
+    }
     tar {
         visible = true
         canBeConsumed = true
@@ -22,7 +25,7 @@ configurations {
 
 dependencies {
     embedded project(path: ":common", configuration: 'archives')
-    embedded project(path: ":loader", configuration: 'archives')
+    embedded project(path: ":loader", configuration: 'embed')
 }
 
 java {

launcher/src/main/java/net/woggioni/envelope/Launcher.java

@@ -10,16 +10,27 @@ import java.io.Reader;
 import java.lang.reflect.Method;
 import java.net.URI;
 import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
 import java.nio.file.Paths;
+import java.util.AbstractMap;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.Enumeration;
 import java.util.List;
 import java.util.Map;
 import java.util.Properties;
+import java.util.TreeMap;
 import java.util.function.Consumer;
+import java.util.function.Function;
 import java.util.jar.Attributes;
 import java.util.jar.JarEntry;
 import java.util.jar.Manifest;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+import static net.woggioni.envelope.Common.or;
+import static net.woggioni.envelope.Constants.EXTRA_CLASSPATH_ENTRY_SEPARATOR;
 
 public class Launcher {
 
@@ -53,6 +64,69 @@ public class Launcher {
         }
     }
 
+    private static Map<String, Map<String, Object>> createContextMap() {
+        Map<String, Map<String, Object>> dictMap = new TreeMap<>();
+        dictMap.put("env", Collections.unmodifiableMap(System.getenv()
+            .entrySet()
+            .stream()
+            .map(entry -> new AbstractMap.SimpleEntry<>(entry.getKey(), (Object) entry.getValue()))
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))));
+        dictMap.put("sys", Collections.unmodifiableMap(System.getProperties().entrySet().stream()
+            .map((Map.Entry<? super String, Object> entry) -> (Map.Entry<String, Object>) entry)
+            .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue))));
+        return Collections.unmodifiableMap(dictMap);
+    }
+
+    private static Stream<JarFile> getExtraClasspath(Attributes mainAttributes) {
+        return Common.opt2Stream(or(
+                    () -> System.getProperty(Constants.JvmProperties.EXTRA_CLASSPATH),
+                    () -> mainAttributes.getValue(Constants.ManifestAttributes.EXTRA_CLASSPATH)
+                )
+                .map(manifestAttribute -> {
+                    Map<String, Map<String, Object>> dictMap = createContextMap();
+                    return Common.renderTemplate(manifestAttribute, Collections.emptyMap(), dictMap);
+                }).map(extraClasspathString -> {
+                    List<String> paths = new ArrayList<>();
+                    int cursor = 0;
+                    while(true) {
+                        int sep = Common.indexOfWithEscape(
+                            extraClasspathString,
+                            EXTRA_CLASSPATH_ENTRY_SEPARATOR,
+                            EXTRA_CLASSPATH_ENTRY_SEPARATOR,
+                            cursor,
+                            extraClasspathString.length()
+                        );
+                        String classpathEntry = extraClasspathString.substring(cursor, sep < 0 ? extraClasspathString.length() : sep);
+                        paths.add(classpathEntry);
+                        if(sep < 0) break;
+                        cursor = sep + 1;
+                    }
+                    return paths;
+                }))
+            .flatMap(List::stream)
+            .map(Paths::get)
+            .flatMap(new Function<Path, Stream<Path>>() {
+                @Override
+                @SneakyThrows
+                public Stream<Path> apply(Path path) {
+                    if(Files.isDirectory(path)) {
+                        return Files.list(path).filter(childPath -> !Files.isDirectory(childPath));
+                    } else {
+                        return Stream.of(path);
+                    }
+                }
+            })
+            .filter(path -> path.getFileName().toString().toLowerCase().endsWith(".jar"))
+            .map(Path::toFile)
+            .map(new Function<File, JarFile>() {
+                @Override
+                @SneakyThrows
+                public JarFile apply(File file) {
+                    return new JarFile(file);
+                }
+            });
+    }
+
     @SneakyThrows
     public static void main(String[] args) {
         Enumeration<URL> it = Launcher.class.getClassLoader().getResources(Constants.SYSTEM_PROPERTIES_FILE);
@@ -73,8 +147,14 @@ public class Launcher {
         Manifest mf = currentJar.getManifest();
         Attributes mainAttributes = mf.getMainAttributes();
 
-        String mainClassName = mainAttributes.getValue(Constants.ManifestAttributes.MAIN_CLASS);
-        String mainModuleName = mainAttributes.getValue(Constants.ManifestAttributes.MAIN_MODULE);
+        String mainClassName = or(
+            () -> System.getProperty(Constants.JvmProperties.MAIN_CLASS),
+            () -> mainAttributes.getValue(Constants.ManifestAttributes.MAIN_CLASS)
+        ).orElse(null);
+        String mainModuleName = or(
+            () -> System.getProperty(Constants.JvmProperties.MAIN_MODULE),
+            () -> mainAttributes.getValue(Constants.ManifestAttributes.MAIN_MODULE)
+        ).orElse(null);
         StringBuilder sb = new StringBuilder();
         List<JarFile> classpath = new ArrayList<>();
         URL libraryTocResource = Launcher.class.getClassLoader().getResource(Constants.LIBRARIES_TOC);
@@ -94,6 +174,8 @@ public class Launcher {
                 else sb.append((char) c);
             }
         }
+
+        getExtraClasspath(mainAttributes).forEach(classpath::add);
         Consumer<Class<?>> runner = new Consumer<Class<?>>() {
             @Override
             @SneakyThrows

launcher/src/main/java11/net/woggioni/envelope/MainRunner.java

@@ -85,6 +85,7 @@ class MainRunner {
             ModuleLayer layer = controller.layer();
             Module mainModule = layer.findModule(mainModuleName).orElseThrow(
                     () -> new IllegalStateException(String.format("Main module '%s' not found", mainModuleName)));
+            Thread.currentThread().setContextClassLoader(mainModule.getClassLoader());
             Optional<String> mainClassOpt = Optional.ofNullable(mainClassName);
             runner.accept(Optional.ofNullable(mainClassName)
                 .or(() -> mainModule.getDescriptor().mainClass())

loader/build.gradle

@@ -7,11 +7,14 @@ ext {
     setProperty('jpms.module.name', 'net.woggioni.envelope.loader')
 }
 
-compileJava11 {
-    exclude('module-info.java')
+configurations {
+    embed {
+        canBeResolved = true
+        canBeConsumed = true
+        visible = true
+        transitive = true
+    }
 }
-
-
 
 publishing {
     publications {
@@ -24,3 +27,24 @@ publishing {
     }
 }
 
+
+tasks.register('embedJar', Jar) { jar ->
+    Provider<Jar> jarTaskProvider = tasks.named(JavaPlugin.JAR_TASK_NAME)
+    jar.inputs.files(jarTaskProvider)
+    archiveClassifier = 'embed'
+    from(zipTree(jarTaskProvider.map { it.archiveFile} )) {
+        exclude '**/module-info.class'
+    }
+    manifest{
+        attributes([
+            'Multi-Release': 'true'
+        ])
+    }
+}
+
+
+
+artifacts {
+    embed(embedJar)
+}
+

loader/src/main/java11/net.woggioni.envelope.loader/JarFileModuleFinder.java

@@ -4,9 +4,11 @@ import lombok.SneakyThrows;
 import net.woggioni.envelope.loader.JarFile;
 import net.woggioni.envelope.loader.jar.Handler;
 
+import java.io.BufferedReader;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
+import java.io.InputStreamReader;
 import java.lang.module.ModuleDescriptor;
 import java.lang.module.ModuleFinder;
 import java.lang.module.ModuleReader;
@@ -17,6 +19,8 @@ import java.net.URLStreamHandler;
 import java.nio.file.Paths;
 import java.util.AbstractMap;
 import java.util.Arrays;
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.Map;
@@ -27,16 +31,20 @@ import java.util.TreeMap;
 import java.util.jar.Attributes.Name;
 import java.util.jar.JarEntry;
 import java.util.jar.Manifest;
+import java.util.jar.Attributes;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import java.lang.module.FindException;
+import java.nio.charset.StandardCharsets;
+import java.lang.module.InvalidModuleDescriptorException;
 
 public class JarFileModuleFinder implements ModuleFinder {
 
     private static final String MODULE_DESCRIPTOR_ENTRY = "module-info.class";
     private static final Name AUTOMATIC_MODULE_NAME_MANIFEST_ENTRY = new Name("Automatic-Module-Name");
-
+    private static final String SERVICES_PREFIX = "META-INF/services/";
     private static class Patterns {
         static final Pattern DASH_VERSION = Pattern.compile("-(\\d+(\\.|$))");
         static final Pattern NON_ALPHANUM = Pattern.compile("[^A-Za-z0-9]");
@@ -44,6 +52,66 @@ public class JarFileModuleFinder implements ModuleFinder {
         static final Pattern LEADING_DOTS = Pattern.compile("^\\.");
         static final Pattern TRAILING_DOTS = Pattern.compile("\\.$");
     }
+
+
+    // keywords, boolean and null literals, not allowed in identifiers
+    private static final Set<String> RESERVED = Set.of(
+        "abstract",
+        "assert",
+        "boolean",
+        "break",
+        "byte",
+        "case",
+        "catch",
+        "char",
+        "class",
+        "const",
+        "continue",
+        "default",
+        "do",
+        "double",
+        "else",
+        "enum",
+        "extends",
+        "final",
+        "finally",
+        "float",
+        "for",
+        "goto",
+        "if",
+        "implements",
+        "import",
+        "instanceof",
+        "int",
+        "interface",
+        "long",
+        "native",
+        "new",
+        "package",
+        "private",
+        "protected",
+        "public",
+        "return",
+        "short",
+        "static",
+        "strictfp",
+        "super",
+        "switch",
+        "synchronized",
+        "this",
+        "throw",
+        "throws",
+        "transient",
+        "try",
+        "void",
+        "volatile",
+        "while",
+        "true",
+        "false",
+        "null",
+        "_"
+    );
+
     private final Map<String, Map.Entry<ModuleReference, Handler>> modules;
 
     @SneakyThrows
@@ -150,20 +218,7 @@ public class JarFileModuleFinder implements ModuleFinder {
                     moduleDescriptor = ModuleDescriptor.read(is, () -> collectPackageNames(jarFile));
                 }
             } else {
-                Manifest mf = jarFile.getManifest();
-                moduleName = mf.getMainAttributes().getValue(AUTOMATIC_MODULE_NAME_MANIFEST_ENTRY);
-                if(moduleName == null) {
-                    moduleName = moduleNameFromURI(uri);
-                }
-                ModuleDescriptor.Builder mdb = ModuleDescriptor.newAutomaticModule(moduleName);
-                mdb.packages(collectPackageNames(jarFile));
-
-                // Main-Class attribute if it exists
-                String mainClass = mf.getMainAttributes().getValue(Name.MAIN_CLASS);
-                if (mainClass != null) {
-                    mdb.mainClass(mainClass);
-                }
-                moduleDescriptor = mdb.build();
+                  moduleDescriptor = deriveModuleDescriptor(jarFile);
             }
         
             modules.put(moduleDescriptor.name(),
@@ -210,4 +265,233 @@ public class JarFileModuleFinder implements ModuleFinder {
             .stream().map(Map.Entry::getKey)
             .collect(Collectors.toSet()));
     }
+
+    private ModuleDescriptor deriveModuleDescriptor(JarFile jf)
+        throws IOException
+    {
+        // Read Automatic-Module-Name attribute if present
+        Manifest man = jf.getManifest();
+        Attributes attrs = null;
+        String moduleName = null;
+        if (man != null) {
+            attrs = man.getMainAttributes();
+            if (attrs != null) {
+                moduleName = attrs.getValue(AUTOMATIC_MODULE_NAME_MANIFEST_ENTRY);
+            }
+        }
+
+        // Derive the version, and the module name if needed, from JAR file name
+        String fn = jf.getName();
+        int i = fn.lastIndexOf(File.separator);
+        if (i != -1)
+            fn = fn.substring(i + 1);
+
+        // drop ".jar"
+        String name = fn.substring(0, fn.length() - 4);
+        String vs = null;
+
+        // find first occurrence of -${NUMBER}. or -${NUMBER}$
+        Matcher matcher = Patterns.DASH_VERSION.matcher(name);
+        if (matcher.find()) {
+            int start = matcher.start();
+
+            // attempt to parse the tail as a version string
+            try {
+                String tail = name.substring(start + 1);
+                ModuleDescriptor.Version.parse(tail);
+                vs = tail;
+            } catch (IllegalArgumentException ignore) { }
+
+            name = name.substring(0, start);
+        }
+
+        // Create builder, using the name derived from file name when
+        // Automatic-Module-Name not present
+        ModuleDescriptor.Builder builder;
+        if (moduleName != null) {
+            try {
+                builder = ModuleDescriptor.newAutomaticModule(moduleName);
+            } catch (IllegalArgumentException e) {
+                throw new FindException(AUTOMATIC_MODULE_NAME_MANIFEST_ENTRY + ": " + e.getMessage());
+            }
+        } else {
+            builder = ModuleDescriptor.newAutomaticModule(cleanModuleName(name));
+        }
+
+        // module version if present
+        if (vs != null)
+            builder.version(vs);
+
+        // scan the names of the entries in the JAR file
+        Map<Boolean, Set<String>> map = jf.versionedStream()
+            .filter(e -> !e.isDirectory())
+            .map(JarEntry::getName)
+            .filter(e -> (e.endsWith(".class") ^ e.startsWith(SERVICES_PREFIX)))
+            .collect(Collectors.partitioningBy(e -> e.startsWith(SERVICES_PREFIX),
+                Collectors.toSet()));
+
+        Set<String> classFiles = map.get(Boolean.FALSE);
+        Set<String> configFiles = map.get(Boolean.TRUE);
+
+        // the packages containing class files
+        Set<String> packages = classFiles.stream()
+            .map(this::toPackageName)
+            .flatMap(Optional::stream)
+            .distinct()
+            .collect(Collectors.toSet());
+
+        // all packages are exported and open
+        builder.packages(packages);
+
+        // map names of service configuration files to service names
+        Set<String> serviceNames = configFiles.stream()
+            .map(this::toServiceName)
+            .flatMap(Optional::stream)
+            .collect(Collectors.toSet());
+
+        // parse each service configuration file
+        for (String sn : serviceNames) {
+            JarEntry entry = jf.getJarEntry(SERVICES_PREFIX + sn);
+            List<String> providerClasses = new ArrayList<>();
+            try (InputStream in = jf.getInputStream(entry)) {
+                BufferedReader reader
+                    = new BufferedReader(new InputStreamReader(in, StandardCharsets.UTF_8));
+                String cn;
+                while ((cn = nextLine(reader)) != null) {
+                    if (!cn.isEmpty()) {
+                        String pn = packageName(cn);
+                        if (!packages.contains(pn)) {
+                            String msg = "Provider class " + cn + " not in module";
+                            throw new InvalidModuleDescriptorException(msg);
+                        }
+                        providerClasses.add(cn);
+                    }
+                }
+            }
+            if (!providerClasses.isEmpty())
+                builder.provides(sn, providerClasses);
+        }
+
+        // Main-Class attribute if it exists
+        if (attrs != null) {
+            String mainClass = attrs.getValue(Attributes.Name.MAIN_CLASS);
+            if (mainClass != null) {
+                mainClass = mainClass.replace('/', '.');
+                if (isClassName(mainClass)) {
+                    String pn = packageName(mainClass);
+                    if (packages.contains(pn)) {
+                        builder.mainClass(mainClass);
+                    }
+                }
+            }
+        }
+
+        return builder.build();
+    }
+
+    private Optional<String> toServiceName(String cf) {
+        assert cf.startsWith(SERVICES_PREFIX);
+        int index = cf.lastIndexOf("/") + 1;
+        if (index < cf.length()) {
+            String prefix = cf.substring(0, index);
+            if (prefix.equals(SERVICES_PREFIX)) {
+                String sn = cf.substring(index);
+                if (isClassName(sn))
+                    return Optional.of(sn);
+            }
+        }
+        return Optional.empty();
+    }
+
+    private static String packageName(String cn) {
+        int index = cn.lastIndexOf('.');
+        return (index == -1) ? "" : cn.substring(0, index);
+    }
+
+    /**
+     * Maps the name of an entry in a JAR or ZIP file to a package name.
+     *
+     * @throws InvalidModuleDescriptorException if the name is a class file in
+     *         the top-level directory of the JAR/ZIP file (and it's not
+     *         module-info.class)
+     */
+    private Optional<String> toPackageName(String name) {
+        assert !name.endsWith("/");
+        int index = name.lastIndexOf("/");
+        if (index == -1) {
+            if (name.endsWith(".class") && !name.equals(MODULE_DESCRIPTOR_ENTRY)) {
+                String msg = name + " found in top-level directory"
+                    + " (unnamed package not allowed in module)";
+                throw new InvalidModuleDescriptorException(msg);
+            }
+            return Optional.empty();
+        }
+
+        String pn = name.substring(0, index).replace('/', '.');
+        if (isPackageName(pn)) {
+            return Optional.of(pn);
+        } else {
+            // not a valid package name
+            return Optional.empty();
+        }
+    }
+
+    /**
+     * Reads the next line from the given reader and trims it of comments and
+     * leading/trailing white space.
+     *
+     * Returns null if the reader is at EOF.
+     */
+    private String nextLine(BufferedReader reader) throws IOException {
+        String ln = reader.readLine();
+        if (ln != null) {
+            int ci = ln.indexOf('#');
+            if (ci >= 0)
+                ln = ln.substring(0, ci);
+            ln = ln.trim();
+        }
+        return ln;
+    }
+
+    private static boolean isClassName(String name) {
+        return isTypeName(name);
+    }
+
+    /**
+     * Returns {@code true} if the given name is a legal type name.
+     */    private static boolean isPackageName(String name) {
+        return isTypeName(name);
+    }
+
+    private static boolean isTypeName(String name) {
+        int next;
+        int off = 0;
+        while ((next = name.indexOf('.', off)) != -1) {
+            String id = name.substring(off, next);
+            if (!isJavaIdentifier(id))
+                return false;
+            off = next+1;
+        }
+        String last = name.substring(off);
+        return isJavaIdentifier(last);
+    }
+
+    private static boolean isJavaIdentifier(String str) {
+        if (str.isEmpty() || RESERVED.contains(str))
+            return false;
+
+        int first = Character.codePointAt(str, 0);
+        if (!Character.isJavaIdentifierStart(first))
+            return false;
+
+        int i = Character.charCount(first);
+        while (i < str.length()) {
+            int cp = Character.codePointAt(str, i);
+            if (!Character.isJavaIdentifierPart(cp))
+                return false;
+            i += Character.charCount(cp);
+        }
+
+        return true;
+    }
 }

src/main/java/net/woggioni/gradle/envelope/EnvelopeJarTask.java

@@ -18,8 +18,11 @@ import org.gradle.api.internal.file.copy.CopyActionProcessingStream;
 import org.gradle.api.internal.file.copy.FileCopyDetailsInternal;
 import org.gradle.api.java.archives.internal.DefaultManifest;
 import org.gradle.api.model.ObjectFactory;
+import org.gradle.api.plugins.BasePlugin;
 import org.gradle.api.plugins.BasePluginExtension;
 import org.gradle.api.plugins.JavaApplication;
+import org.gradle.api.provider.ListProperty;
+import org.gradle.api.provider.MapProperty;
 import org.gradle.api.provider.Property;
 import org.gradle.api.provider.Provider;
 import org.gradle.api.tasks.Input;
@@ -59,10 +62,12 @@ import java.util.zip.ZipOutputStream;
 
 import static java.util.zip.Deflater.BEST_COMPRESSION;
 import static java.util.zip.Deflater.NO_COMPRESSION;
+import static net.woggioni.gradle.envelope.EnvelopePlugin.ENVELOPE_GROUP_NAME;
 
 @SuppressWarnings({"unused" })
-public class EnvelopeJarTask extends AbstractArchiveTask {
+public abstract class EnvelopeJarTask extends AbstractArchiveTask {
 
+    private static final String DEFAULT_ARCHIVE_APPENDIX = ENVELOPE_GROUP_NAME;
     private static final String MINIMUM_GRADLE_VERSION = "6.0";
     private static final String EXTRACT_LAUNCHER_TASK_NAME = "extractEnvelopeLauncher";
 
@@ -75,16 +80,21 @@ public class EnvelopeJarTask extends AbstractArchiveTask {
 
     private final Provider<ExtractLauncherTask> extractLauncherTaskProvider;
 
-    @Getter(onMethod_ = {@Input, @Optional})
-    private final Property<String> mainClass;
+    @Input
+    @Optional
+    public abstract Property<String> getMainClass();
 
-    @Getter(onMethod_ = {@Input, @Optional})
-    private final Property<String> mainModule;
+    @Input
+    @Optional
+    public abstract Property<String> getMainModule();
 
     private final Properties javaAgents = new Properties();
 
-    @Getter(onMethod_ = {@Input})
-    private final Map<String, String> systemProperties = new TreeMap<>();
+    @Input
+    public abstract MapProperty<String, String> getSystemProperties();
+
+    @Input
+    public abstract ListProperty<String> getExtraClasspath();
 
     private final org.gradle.api.java.archives.Manifest manifest;
 
@@ -124,10 +134,6 @@ public class EnvelopeJarTask extends AbstractArchiveTask {
         javaAgents.put(className, args);
     }
 
-    public void systemProperty(String key, String value) {
-        systemProperties.put(key, value);
-    }
-
     public void includeLibraries(Object... files) {
         into(Constants.LIBRARIES_FOLDER, (copySpec) -> copySpec.from(files));
     }
@@ -135,31 +141,30 @@ public class EnvelopeJarTask extends AbstractArchiveTask {
 
     @Inject
     public EnvelopeJarTask(ObjectFactory objects, FileResolver fileResolver) {
-        Project rootProject = getProject().getRootProject();
-        TaskContainer rootProjectTasks = rootProject.getTasks();
-        if(rootProjectTasks.getNames().contains(EXTRACT_LAUNCHER_TASK_NAME)) {
-            extractLauncherTaskProvider = rootProjectTasks.named(EXTRACT_LAUNCHER_TASK_NAME, ExtractLauncherTask.class);
+        Project project = getProject();
+        TaskContainer tasks = project.getTasks();
+        if(tasks.getNames().contains(EXTRACT_LAUNCHER_TASK_NAME)) {
+            extractLauncherTaskProvider = tasks.named(EXTRACT_LAUNCHER_TASK_NAME, ExtractLauncherTask.class);
         } else {
-            extractLauncherTaskProvider = rootProject.getTasks().register(EXTRACT_LAUNCHER_TASK_NAME, ExtractLauncherTask.class);
+            extractLauncherTaskProvider = tasks.register(EXTRACT_LAUNCHER_TASK_NAME, ExtractLauncherTask.class);
         }
         getInputs().files(extractLauncherTaskProvider);
 
-        setGroup("build");
+        setGroup(BasePlugin.BUILD_GROUP);
         setDescription("Creates an executable jar file, embedding all of its runtime dependencies");
         BasePluginExtension basePluginExtension = getProject().getExtensions().getByType(BasePluginExtension.class);
-        getDestinationDirectory().set(basePluginExtension.getDistsDirectory());
+        getDestinationDirectory().set(basePluginExtension.getLibsDirectory());
         getArchiveBaseName().convention(getProject().getName());
         getArchiveExtension().convention("jar");
         getArchiveVersion().convention(getProject().getVersion().toString());
-        getArchiveAppendix().convention("envelope");
+        getArchiveAppendix().convention(DEFAULT_ARCHIVE_APPENDIX);
 
         manifest = new DefaultManifest(fileResolver);
-        mainClass = objects.property(String.class);
-        mainModule = objects.property(String.class);
+        getSystemProperties().convention(new TreeMap<>());
         JavaApplication javaApplication = getProject().getExtensions().findByType(JavaApplication.class);
         if(!Objects.isNull(javaApplication)) {
-            mainClass.convention(javaApplication.getMainClass());
-            mainModule.convention(javaApplication.getMainModule());
+            getMainClass().convention(javaApplication.getMainClass());
+            getMainModule().convention(javaApplication.getMainModule());
         }
         from(getProject().tarTree(extractLauncherTaskProvider.map(ExtractLauncherTask::getLauncherTar)), copySpec -> exclude(JarFile.MANIFEST_NAME));
     }
@@ -286,11 +291,23 @@ public class EnvelopeJarTask extends AbstractArchiveTask {
                 mainAttributes.put(new Attributes.Name("Launcher-Agent-Class"), Constants.AGENT_LAUNCHER);
                 mainAttributes.put(new Attributes.Name("Can-Redefine-Classes"), "true");
                 mainAttributes.put(new Attributes.Name("Can-Retransform-Classes"), "true");
-                if(mainClass.isPresent()) {
-                    mainAttributes.putValue(Constants.ManifestAttributes.MAIN_CLASS, mainClass.get());
+                String separator = "" + Constants.EXTRA_CLASSPATH_ENTRY_SEPARATOR;
+                ListProperty<String> extraClasspathProperty = EnvelopeJarTask.this.getExtraClasspath();
+                java.util.Optional.of(extraClasspathProperty)
+                    .filter(ListProperty::isPresent)
+                    .map(ListProperty::get)
+                    .filter(l -> !l.isEmpty())
+                    .ifPresent(extraClasspath -> {
+                        String extraClasspathString = extraClasspath.stream()
+                            .map(it -> it.replace(separator, separator + separator)
+                            ).collect(Collectors.joining(separator));
+                        mainAttributes.put(new Attributes.Name(Constants.ManifestAttributes.EXTRA_CLASSPATH), extraClasspathString);
+                    });
+                if(getMainClass().isPresent()) {
+                    mainAttributes.putValue(Constants.ManifestAttributes.MAIN_CLASS, getMainClass().get());
                 }
-                if(mainModule.isPresent()) {
-                    mainAttributes.putValue(Constants.ManifestAttributes.MAIN_MODULE, mainModule.get());
+                if(getMainModule().isPresent()) {
+                    mainAttributes.putValue(Constants.ManifestAttributes.MAIN_MODULE, getMainModule().get());
                 }
 
                 MessageDigest md = MessageDigest.getInstance("SHA-256");
@@ -334,7 +351,7 @@ public class EnvelopeJarTask extends AbstractArchiveTask {
                     zipEntry.setMethod(ZipEntry.DEFLATED);
                     zipOutputStream.putNextEntry(zipEntry);
                     Properties props = new Properties();
-                    for(Map.Entry<String, String> entry : systemProperties.entrySet()) {
+                    for(Map.Entry<String, String> entry : getSystemProperties().get().entrySet()) {
                         props.setProperty(entry.getKey(), entry.getValue());
                     }
                     props.store(zipOutputStream, null);

src/main/java/net/woggioni/gradle/envelope/EnvelopePlugin.java

@@ -10,10 +10,14 @@ import org.gradle.api.tasks.JavaExec;
 import org.gradle.api.tasks.bundling.Jar;
 
 public class EnvelopePlugin implements Plugin<Project> {
+
+    public static final String ENVELOPE_GROUP_NAME = "envelope";
+
     @Override
     public void apply(Project project) {
+        project.getPluginManager().apply(JavaPlugin.class);
         Provider<EnvelopeJarTask> envelopeJarTaskProvider = project.getTasks().register("envelopeJar", EnvelopeJarTask.class, t -> {
-            t.setGroup(BasePlugin.BUILD_GROUP);
+            t.setGroup(ENVELOPE_GROUP_NAME);
             t.setDescription("Package the application in a single executable jar file");
             t.includeLibraries(project.getConfigurations().named(JavaPlugin.RUNTIME_CLASSPATH_CONFIGURATION_NAME));
             t.includeLibraries(project.getTasks().named(JavaPlugin.JAR_TASK_NAME, Jar.class));
@@ -23,7 +27,7 @@ public class EnvelopePlugin implements Plugin<Project> {
         });
         Provider<JavaExec> envelopeRunTaskProvider = project.getTasks().register("envelopeRun", JavaExec.class, t -> {
             t.getInputs().files(envelopeJarTaskProvider);
-            t.setGroup("envelope");
+            t.setGroup(ENVELOPE_GROUP_NAME);
             t.setDescription("Run the application in the envelope jar");
             t.classpath(envelopeJarTaskProvider);
         });