*
     * @param conn
     *            {@link JarURLConnection}。{@literal null}であってはいけません
     * @return {@link JarFile}
     */
    public static JarFile getJarFile(final JarURLConnection conn) {
        assertArgumentNotNull("conn", conn);

        try {
            return conn.getJarFile();
        } catch (final IOException e) {
            throw new IORuntimeException(e);
        }

     */
    public ExtensionDescriptor build(File extensionJar) throws IOException {
        ExtensionDescriptor extensionDescriptor = null;

        if (extensionJar.isFile()) {
            try (JarFile pluginJar = new JarFile(extensionJar, false)) {
                ZipEntry pluginDescriptorEntry = pluginJar.getEntry(getExtensionDescriptorLocation());

                if (pluginDescriptorEntry != null) {

        assertArgumentNotNull("jarFile", jarFile);

        try {
            jarFile.close();
        } catch (final IOException e) {
            logger.log(format("ECL0017", e.getMessage()), e);
        }
    }

    File jarFile = File.createTempFile("with_circular_class_path", ".jar");
    try {
      writeSelfReferencingJarFile(jarFile, "test.txt");
      assertThat(
              new ClassPath.LocationInfo(jarFile, ClassPathTest.class.getClassLoader())
                  .scanResources())
          .hasSize(1);
    } finally {
      jarFile.delete();
    }
  }

    File jarFile = File.createTempFile("with_circular_class_path", ".jar");
    try {
      writeSelfReferencingJarFile(jarFile, "test.txt");
      assertThat(
              new ClassPath.LocationInfo(jarFile, ClassPathTest.class.getClassLoader())
                  .scanResources())
          .hasSize(1);
    } finally {
      jarFile.delete();
    }
  }

        createJar(classGraph, classesDir, manifestFile, jarFile)

        return jarFile
    }

    private
    fun createJar(classGraph: ClassGraph, classesDir: File, manifestFile: File, jarFile: File) {
        try {
            JarOutputStream(BufferedOutputStream(FileOutputStream(jarFile))).use { jarOutputStream ->
                if (manifestFile.exists()) {

    /**
     * Jarファイル形式のファイルに含まれるリソースをトラバースします。
     *
     * @param jarFile
     *            jarファイル形式のファイル。{@literal null}であってはいけません
     * @param handler
     *            リソースを処理するハンドラ。{@literal null}であってはいけません
     */
    public static void forEach(final JarFile jarFile, final ResourceHandler handler) {
        assertArgumentNotNull("jarFile", jarFile);
        assertArgumentNotNull("handler", handler);

import java.io.IOException
import java.util.Properties
import java.util.jar.JarEntry
import java.util.jar.JarFile


data class PluginEntry(val pluginId: String, val implementationClass: String)


fun pluginEntriesFrom(jar: File): List<PluginEntry> = try {
    JarFile(jar, false).use { jarFile ->
        jarFile.entries().asSequence().filter {
            isGradlePluginPropertiesFile(it)
        }.map { pluginEntry ->

        for (final WebResource possibleJar : possibleJars) {
            if (possibleJar.isFile() && possibleJar.getName().endsWith(".jar")) {
                try (final JarFile jarFile = new JarFile(possibleJar.getCanonicalPath())) {
                    final Manifest manifest = jarFile.getManifest();
                    if (manifest != null && manifest.getEntries() != null) {
                        final Attributes attributes = manifest.getMainAttributes();

    protected List<String> loadDataStoreNameList() {
        final Set<String> nameSet = new HashSet<>();
        final File[] jarFiles = ResourceUtil.getPluginJarFiles(PluginHelper.ArtifactType.DATA_STORE.getId());
        for (final File jarFile : jarFiles) {
            try (FileSystem fs = FileSystems.newFileSystem(jarFile.toPath(), ClassLoader.getSystemClassLoader())) {
                final Path xmlPath = fs.getPath("fess_ds++.xml");