资源路径前多一个斜杠，为什么换个 API 就读不到配置？

import java.io.IOException;
import java.io.InputStream;
import java.net.URL;
import java.net.URLClassLoader;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.Comparator;
import java.util.List;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;
import java.util.stream.Stream;
import javax.tools.JavaCompiler;
import javax.tools.ToolProvider;

public final class Main {
    private static int checks;
    private static void check(boolean ok, String message) {
        checks++;
        if (!ok) throw new AssertionError(message);
    }
    private static String read(InputStream stream) throws IOException {
        if (stream == null) return "<missing>";
        try (stream) {
            return new String(stream.readAllBytes(), StandardCharsets.UTF_8);
        }
    }
    private static void observe(String label, String name, InputStream stream, String expected) throws IOException {
        String value = read(stream);
        check(value.equals(expected), label + " " + name + " returned " + value);
        System.out.println(label + " " + name + " -> " + value);
    }
    private static void inspect(String label, URL location) throws Exception {
        // The platform parent avoids inheriting application class-path resources.
        try (URLClassLoader loader = new URLClassLoader(new URL[]{location}, ClassLoader.getPlatformClassLoader())) {
            Class<?> anchor = Class.forName("sample.Anchor", true, loader);
            check(anchor.getClassLoader() == loader, "fixture loaded by the isolated loader");
            check(!anchor.getModule().isNamed(), "fixture uses an unnamed module");
            URL resource = anchor.getResource("settings.txt");
            check(resource != null && resource.getProtocol().equals(label.equals("directory") ? "file" : "jar"),
                    "resource comes from the intended directory or JAR");
            observe(label, "Class:settings.txt", anchor.getResourceAsStream("settings.txt"), "package-value");
            observe(label, "Class:/settings.txt", anchor.getResourceAsStream("/settings.txt"), "root-value");
            observe(label, "Class:/sample/settings.txt", anchor.getResourceAsStream("/sample/settings.txt"), "package-value");
            observe(label, "Loader:sample/settings.txt", loader.getResourceAsStream("sample/settings.txt"), "package-value");
            observe(label, "Loader:settings.txt", loader.getResourceAsStream("settings.txt"), "root-value");
            observe(label, "Loader:/sample/settings.txt", loader.getResourceAsStream("/sample/settings.txt"), "<missing>");
            observe(label, "Class:missing.txt", anchor.getResourceAsStream("missing.txt"), "<missing>");
        }
    }
    private static void cleanOwnDirectory(Path root) throws IOException {
        Path boundary = root.toAbsolutePath().normalize();
        try (Stream<Path> walk = Files.walk(boundary)) {
            List<Path> paths = walk.sorted(Comparator.reverseOrder()).toList();
            for (Path path : paths) {
                Path normalized = path.toAbsolutePath().normalize();
                if (!normalized.startsWith(boundary)) throw new IOException("Cleanup escaped its own temporary root");
                Files.deleteIfExists(normalized);
            }
        }
    }
    public static void main(String[] args) throws Exception {
        JavaCompiler compiler = ToolProvider.getSystemJavaCompiler();
        if (compiler == null) throw new IllegalStateException("Run with a full JDK including jdk.compiler");
        Path temp = Files.createTempDirectory("qinghuan-resource-demo-").toAbsolutePath().normalize();
        try {
            Path classes = Files.createDirectories(temp.resolve("classes"));
            Path source = temp.resolve("Anchor.java");
            Files.writeString(source, "package sample; public final class Anchor {}\n", StandardCharsets.UTF_8);
            int result = compiler.run(null, null, null, "-encoding", "UTF-8", "--release", "17",
                    "-d", classes.toString(), source.toString());
            check(result == 0, "fixture compilation succeeded");
            Files.writeString(classes.resolve("settings.txt"), "root-value", StandardCharsets.UTF_8);
            Files.writeString(classes.resolve("sample/settings.txt"), "package-value", StandardCharsets.UTF_8);
            inspect("directory", classes.toUri().toURL());

            Path archive = temp.resolve("fixture.jar");
            try (JarOutputStream jar = new JarOutputStream(Files.newOutputStream(archive))) {
                for (String name : List.of("sample/Anchor.class", "settings.txt", "sample/settings.txt")) {
                    jar.putNextEntry(new JarEntry(name));
                    Files.copy(classes.resolve(name), jar);
                    jar.closeEntry();
                }
            }
            inspect("jar", archive.toUri().toURL());
        } finally {
            cleanOwnDirectory(temp);
        }
        check(!Files.exists(temp), "only the generated temporary fixture was removed");
        System.out.println("temporary-fixture-removed=true");
        System.out.println("PASS " + checks);
    }
}