*
   * <p><b>Note:</b> Unlike other escapers, URL escapers produce <a
   * href="https://url.spec.whatwg.org/#percent-encode">uppercase</a> hexadecimal sequences.
   *
   */
  public static Escaper urlFormParameterEscaper() {
    return URL_FORM_PARAMETER_ESCAPER;
  }

  private static final Escaper URL_FORM_PARAMETER_ESCAPER =
      new PercentEscaper(URL_FORM_PARAMETER_OTHER_SAFE_CHARS, true);

  /**

   * System#getProperty system property}.
   */
  // TODO(b/65488446): Make this a public API.
  static URL[] parseJavaClassPath() {
    ImmutableList.Builder<URL> urls = ImmutableList.builder();
    for (String entry : Splitter.on(PATH_SEPARATOR.value()).split(JAVA_CLASS_PATH.value())) {
      try {
        try {
          urls.add(new File(entry).toURI().toURL());

  }

  @J2ktIncompatible
  @GwtIncompatible // Class.getClassLoader()
  private URL[] getClassPathUrls() {
    ClassLoader classLoader = getClass().getClassLoader();
    return classLoader instanceof URLClassLoader
        ? ((URLClassLoader) classLoader).getURLs()
        : parseJavaClassPath().toArray(new URL[0]);
  }

  /**

    // Now set the context loader to one that should find the resource.
    URL baseUrl = tempFile.getParentFile().toURI().toURL();
    URLClassLoader loader = new URLClassLoader(new URL[] {baseUrl});
    ClassLoader oldContextLoader = Thread.currentThread().getContextClassLoader();
    try {
      Thread.currentThread().setContextClassLoader(loader);
      URL url = Resources.getResource(tempFile.getName());

   * System#getProperty system property}.
   */
  // TODO(b/65488446): Make this a public API.
  static URL[] parseJavaClassPath() {
    ImmutableList.Builder<URL> urls = ImmutableList.builder();
    for (String entry : Splitter.on(PATH_SEPARATOR.value()).split(JAVA_CLASS_PATH.value())) {
      try {
        try {
          urls.add(new File(entry).toURI().toURL());

    FinalizableReferenceQueue.DecoupledLoader decoupledLoader =
        new FinalizableReferenceQueue.DecoupledLoader() {
          @Override
          URLClassLoader newLoader(URL base) {
            return new DecoupledClassLoader(new URL[] {base});
          }
        };

    Class<?> finalizerCopy = decoupledLoader.loadFinalizer();

    assertNotNull(finalizerCopy);

    FinalizableReferenceQueue.DecoupledLoader decoupledLoader =
        new FinalizableReferenceQueue.DecoupledLoader() {
          @Override
          URLClassLoader newLoader(URL base) {
            return new DecoupledClassLoader(new URL[] {base});
          }
        };

    Class<?> finalizerCopy = decoupledLoader.loadFinalizer();

    assertNotNull(finalizerCopy);

    frq.close();

    return new WeakReference<ClassLoader>(sepLoader);
  }

  private URL[] getClassPathUrls() {
    ClassLoader classLoader = getClass().getClassLoader();
    return classLoader instanceof URLClassLoader
        ? ((URLClassLoader) classLoader).getURLs()
        : parseJavaClassPath().toArray(new URL[0]);
  }

  /**

   * Returns a {@link ByteSource} that reads from the given URL.
   *
   * @since 14.0
   */
  public static ByteSource asByteSource(URL url) {
    return new UrlByteSource(url);
  }

  /** A byte source that reads from a URL using {@link URL#openStream()}. */
  private static final class UrlByteSource extends ByteSource {

    private final URL url;

    private UrlByteSource(URL url) {
      this.url = checkNotNull(url);
    }

  /** Java Runtime Environment version. */
  JAVA_VERSION("java.version"),

  /** Java Runtime Environment vendor. */
  JAVA_VENDOR("java.vendor"),

  /** Java vendor URL. */
  JAVA_VENDOR_URL("java.vendor.url"),

  /** Java installation directory. */
  JAVA_HOME("java.home"),

  /** Java Virtual Machine specification version. */
  JAVA_VM_SPECIFICATION_VERSION("java.vm.specification.version"),