FileSystemPool fails to mount a jar located under a non-ASCII path ("Bad escape")

[sbernard31]

Jetty version(s)
Tested with 12.0.33
Artemis project seems to face the same with 12.0.15

Jetty Environment
ee10 (in my case)

HTTP version

Java version/vendor (use: java -version)
openjdk 17.0.19 2026-04-21
OpenJDK Runtime Environment Temurin-17.0.19+10 (build 17.0.19+10)
OpenJDK 64-Bit Server VM Temurin-17.0.19+10 (build 17.0.19+10, mixed mode, sharing)

OS type/version
Fedora 44

Description
I have an application which embed a jetty server and which serve statically a folder in a Jar.
When I run this application in a folder where path contains "accent" character, then I face :

java.lang.IllegalArgumentException: Bad escape
	at java.base/sun.nio.fs.UnixUriUtils.fromUri(UnixUriUtils.java:88)
	at java.base/sun.nio.fs.UnixFileSystemProvider.getPath(UnixFileSystemProvider.java:102)
	at java.base/java.nio.file.Path.of(Path.java:203)
	at java.base/java.nio.file.Paths.get(Paths.java:98)
	at org.eclipse.jetty.util.resource.FileSystemPool$Bucket.<init>(FileSystemPool.java:400)
	at org.eclipse.jetty.util.resource.FileSystemPool.retain(FileSystemPool.java:311)
	at org.eclipse.jetty.util.resource.FileSystemPool.mount(FileSystemPool.java:140)
	at org.eclipse.jetty.util.resource.ResourceFactoryInternals$CompositeResourceFactory.mountIfNeeded(ResourceFactoryInternals.java:268)
	at org.eclipse.jetty.util.resource.ResourceFactoryInternals$CompositeResourceFactory.newResource(ResourceFactoryInternals.java:225)
	at org.eclipse.jetty.util.resource.ResourceFactoryInternals$LifeCycle.newResource(ResourceFactoryInternals.java:171)
	at org.eclipse.leshan.demo.server.LeshanServerDemo.createJettyServer(LeshanServerDemo.java:307)
	at org.eclipse.leshan.demo.server.LeshanServerDemo.main(LeshanServerDemo.java:117)

OR

java.lang.IllegalArgumentException: Bad escape
	at java.base/sun.nio.fs.UnixUriUtils.fromUri(UnixUriUtils.java:88)
	at java.base/sun.nio.fs.UnixFileSystemProvider.getPath(UnixFileSystemProvider.java:102)
	at java.base/java.nio.file.Path.of(Path.java:203)
	at java.base/java.nio.file.Paths.get(Paths.java:98)
	at org.eclipse.jetty.util.resource.FileSystemPool$Bucket.<init>(FileSystemPool.java:400)
	at org.eclipse.jetty.util.resource.FileSystemPool.retain(FileSystemPool.java:311)
	at org.eclipse.jetty.util.resource.FileSystemPool.mount(FileSystemPool.java:140)
	at org.eclipse.jetty.util.resource.ResourceFactoryInternals$CompositeResourceFactory.mountIfNeeded(ResourceFactoryInternals.java:268)
	at org.eclipse.jetty.util.resource.ResourceFactoryInternals$CompositeResourceFactory.newResource(ResourceFactoryInternals.java:225)
	at org.eclipse.jetty.util.resource.ResourceFactoryInternals$LifeCycle.newResource(ResourceFactoryInternals.java:171)
	at org.eclipse.jetty.util.resource.ResourceFactory.newResource(ResourceFactory.java:344)
	at org.eclipse.jetty.ee10.servlet.ServletContextHandler.newResource(ServletContextHandler.java:810)
	at org.eclipse.jetty.ee10.servlet.ResourceServlet.init(ResourceServlet.java:223)
	at org.eclipse.jetty.ee10.servlet.DefaultServlet.init(DefaultServlet.java:78)
	at jakarta.servlet.GenericServlet.init(GenericServlet.java:178)
	at jakarta.servlet.http.HttpServlet.init(HttpServlet.java:107)
	at org.eclipse.jetty.ee10.servlet.ServletHolder.initServlet(ServletHolder.java:639)
	at org.eclipse.jetty.ee10.servlet.ServletHolder.initialize(ServletHolder.java:426)
	at org.eclipse.jetty.ee10.servlet.ServletHandler.lambda$initialize$1(ServletHandler.java:666)
	at org.eclipse.jetty.util.ExceptionUtil.call(ExceptionUtil.java:369)
	at org.eclipse.jetty.util.ExceptionUtil$MultiException.callAndCatch(ExceptionUtil.java:305)
	at org.eclipse.jetty.ee10.servlet.ServletHandler.lambda$initialize$0(ServletHandler.java:663)
	at java.base/java.util.stream.SortedOps$SizedRefSortingSink.end(SortedOps.java:357)
	at java.base/java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:510)
	at java.base/java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:499)
	at java.base/java.util.stream.StreamSpliterators$WrappingSpliterator.forEachRemaining(StreamSpliterators.java:310)
	at java.base/java.util.stream.Streams$ConcatSpliterator.forEachRemaining(Streams.java:735)
	at java.base/java.util.stream.ReferencePipeline$Head.forEach(ReferencePipeline.java:762)
	at org.eclipse.jetty.ee10.servlet.ServletHandler.initialize(ServletHandler.java:686)
	at org.eclipse.jetty.ee10.servlet.ServletContextHandler.startContext(ServletContextHandler.java:1325)
	at org.eclipse.jetty.ee10.servlet.ServletContextHandler.lambda$doStart$0(ServletContextHandler.java:1051)
	at org.eclipse.jetty.server.handler.ContextHandler$ScopedContext.call(ContextHandler.java:1494)
	at org.eclipse.jetty.ee10.servlet.ServletContextHandler.doStart(ServletContextHandler.java:1048)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:93)
	at org.eclipse.jetty.util.component.ContainerLifeCycle.start(ContainerLifeCycle.java:169)
	at org.eclipse.jetty.server.Server.start(Server.java:643)
	at org.eclipse.jetty.util.component.ContainerLifeCycle.doStart(ContainerLifeCycle.java:120)
	at org.eclipse.jetty.server.Handler$Abstract.doStart(Handler.java:491)
	at org.eclipse.jetty.server.Server.doStart(Server.java:584)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:93)
	at org.eclipse.leshan.demo.server.LeshanServerDemo.main(LeshanServerDemo.java:132)

I'm not 100% sure but It could be a bug ?

Searching on the web I see that another project faced that : https://issues.apache.org/jira/browse/ARTEMIS-5461

How to reproduce?

I'm able to reproduce with

package org.eclipse.leshan.demo.server;

import java.net.URI;
import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;

import org.eclipse.jetty.util.resource.Resource;
import org.eclipse.jetty.util.resource.ResourceFactory;

/**
 * Minimal reproducer for: IllegalArgumentException "Bad escape" thrown from FileSystemPool$Bucket -> Paths.get(URI) ->
 * UnixUriUtils.fromUri when mounting a jar that lives in a directory whose name contains non-ASCII characters.
 *
 * Build/run (adjust the jetty-util version/path to match your setup):
 *
 * JETTY_UTIL=~/.m2/repository/org/eclipse/jetty/jetty-util/12.0.33/jetty-util-12.0.33.jar javac -cp "$JETTY_UTIL"
 * JettyFileSystemPoolReproduction.java java -cp ".:$JETTY_UTIL" JettyFileSystemPoolReproduction
 *
 * Expected: prints "OK ...". Actual (12.0.33, Linux, OpenJDK 21): IllegalArgumentException: Bad escape.
 *
 * Sanity check: change the directory name on line ~31 to an ASCII-only name (e.g. "plain-ascii-dir") and the mount
 * succeeds — confirming the trigger is the non-ASCII characters in the container path, not the jar contents.
 */
public class JettyFileSystemPoolReproduction {

    public static void main(String[] args) throws Exception {
        // 1. A directory whose name contains spaces AND a non-ASCII character.
        Path base = Files.createTempDirectory("jetty-repro-");
        Path dir = Files.createDirectory(base.resolve("un dossier avec dés accents"));
        Path jar = dir.resolve("app.jar");

        // 2. A trivial jar containing a "webapp/" directory entry.
        try (JarOutputStream out = new JarOutputStream(Files.newOutputStream(jar))) {
            out.putNextEntry(new JarEntry("webapp/"));
            out.closeEntry();
            out.putNextEntry(new JarEntry("webapp/index.html"));
            out.write("<html>ok</html>".getBytes(StandardCharsets.UTF_8));
            out.closeEntry();
        }

        // 3. The jar: URI for the bundled "webapp" directory — exactly the form
        // ClassLoader.getResource("webapp") yields (path is percent-encoded).
        URI webappUri = URI.create("jar:" + jar.toUri() + "!/webapp");
        System.out.println("jar.toUri()  = " + jar.toUri());
        System.out.println("mounting     = " + webappUri);

        // 4. Hand the (correctly percent-encoded) URI to Jetty.
        // FileSystemPool mounts the zip filesystem via Paths.get(<container URI>),
        // which throws "Bad escape" when the container path has non-ASCII chars.
        try (ResourceFactory.Closeable factory = ResourceFactory.closeable()) {
            Resource r = factory.newResource(webappUri);
            System.out.println("OK: " + r + " (exists=" + r.exists() + ")");
        }
    }
}

[lorban]

I tried your reproducer and I can reproduce the failure with 12.0.36, as well as 12.1.8. But 12.1.9 and 12.1.10 seem to work just fine.

Could you please give 12.1.10 another try (since you noted that you unsuccessfully tried that version) while we look at the problem?

Thanks!

[joakime]

You've hit a bug in Java itself.

Reproducer, without Jetty involved.

package org.example.jetty;

import java.io.IOException;
import java.net.URI;
import java.net.URISyntaxException;
import java.nio.file.FileSystem;
import java.nio.file.FileSystems;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.HashMap;
import java.util.Map;
import java.util.jar.JarEntry;
import java.util.jar.JarOutputStream;

import static java.nio.charset.StandardCharsets.UTF_8;

public class FileSystemToUriBug
{
    public static void main(String[] args) throws IOException, URISyntaxException
    {
        Path base = Files.createTempDirectory("fs-repro-");
        Path dir = Files.createDirectory(base.resolve("un dossier avec dés accents"));
        Path jar = dir.resolve("app.jar");
        System.out.printf("Jar: %s%n", jar);
        System.out.printf("Jar.URI: %s%n", jar.toUri());

        try (JarOutputStream out = new JarOutputStream(Files.newOutputStream(jar)))
        {
            out.putNextEntry(new JarEntry("dir/"));
            out.closeEntry();
            out.putNextEntry(new JarEntry("dir/index.txt"));
            out.write("OK".getBytes(UTF_8));
            out.closeEntry();
        }

        URI jarFileURI = new URI("jar:" + jar.toUri().toASCIIString() + "!/");
        System.out.printf("jarFileURI: %s%n", jarFileURI);
        Map<String, String> env = new HashMap<>();
        // Key and Value documented at https://docs.oracle.com/en/java/javase/17/docs/api/jdk.zipfs/module-summary.html
        env.put("releaseVersion", "runtime");
        try (FileSystem fileSystem = FileSystems.newFileSystem(jarFileURI, env))
        {
            URI rootURI = fileSystem.getPath("/").toUri(); // returns a badly escaped URI
            System.out.printf("rootURI: %s%n", rootURI);
            Path rootAsPath = Path.of(rootURI); // boom! IllegalArgumentException: Bad escape
            System.out.printf("rootAsPath: %s%n", rootAsPath);
        }
    }
}

The bug seems to be in FileSystem.getPath("/").toUri();, where the dés isn't properly escaped in the resulting URI.
That part of the URI should be escaped to d%C3%A9s.

I filed a bug with bugs.java.com about this, meanwhile I'll see if I can work around this bug in 12.0.x (We don't use the FileSystemPool or this buggy Java API in Jetty 12.1.x)

[joakime]

Opened PR to work around this bug in Jetty 12.0.x

• Issue #15289 - Workaround bug in FileSystem.getPath(String).toUri() with unicode paths #15305

[sbernard31]

Could you please give 12.1.10 another try (since you noted that you unsuccessfully tried that version) while we look at the problem?

@lorban I just give it another try with 12.0.33 and 12.1.10 ... and finally I find same result as you :

• 12.0.33 : ❌ java.lang.IllegalArgumentException: Bad escape.
• 12.1.10 : ✔️ Finally works for me.

Sorry for the "noise" 🙇

Just to let you know, in my code (not the simple snippet to reproduce) I tried both :

// Create static Servlet
DefaultServlet staticServelt = new DefaultServlet();
ServletHolder staticHolder = new ServletHolder(staticServelt);
staticHolder.setInitParameter("baseResource",
        LeshanServerDemo.class.getClassLoader().getResource("webapp").toExternalForm());
staticHolder.setInitParameter("gzip", "true");
staticHolder.setInitParameter("cacheControl", "public, max-age=31536000");
root.addServlet(staticHolder, "/");

And :

// Create static Servlet
// Resolve the bundled "webapp" dir as a proper Resource — no String round-trip
URI webappUri = LeshanServerDemo.class.getClassLoader().getResource("webapp").toURI();
Resource webappResource = ResourceFactory.of(root).newResource(webappUri);
root.setBaseResource(webappResource);

// Static Servlet — no "baseResource" init param; it inherits the context's base resource
DefaultServlet staticServlet = new DefaultServlet();
ServletHolder staticHolder = new ServletHolder(staticServlet);
staticHolder.setInitParameter("gzip", "true");
staticHolder.setInitParameter("cacheControl", "public, max-age=31536000");
root.addServlet(staticHolder, "/");

[sbernard31]

You've hit a bug in Java itself.

@joakime, Sorry I didn't take too much time to dig into that deeper.
But If this is a java bug ? how do we explain that it works with jetty 12.1.10 ?

[joakime]

You've hit a bug in Java itself.

@joakime, Sorry I didn't take too much time to dig into that deeper. But If this is a java bug ? how do we explain that it works with jetty 12.1.10 ?

Jetty 12.1.10 doesn't use FileSystemPool, it's totally deprecated.

• Issue #14824 - Deprecate FileSystemPool #14826

As a result, the particular JVM code that has the bug is never called in Jetty 12.1.10.