Java 9 HttpClient exception when using certain characters in URL query parameters

Question

Here is my sample code. The query is encoded to UTF-8:

HttpRequest request = HttpRequest.newBuilder()
    .header("content-type", "application/json;charset=UTF-8")
    .uri(URI.create("http://localhost:8080/test?param1=test%C5%84"))
    .GET()
    .build();

HttpClient.newBuilder()
    .version(HttpClient.Version.HTTP_2)
    .build()
    .send(request, HttpResponse.BodyHandler.asString(Charset.forName("UTF-8")));

After I run this example I get the following exception:

java.lang.IllegalArgumentException: char=324
at jdk.incubator.httpclient/jdk.incubator.http.internal.hpack.Huffman.codeOf(Huffman.java:559)
at jdk.incubator.httpclient/jdk.incubator.http.internal.hpack.Huffman.lengthOf(Huffman.java:524)
at jdk.incubator.httpclient/jdk.incubator.http.internal.hpack.StringWriter.configure(StringWriter.java:79)
at jdk.incubator.httpclient/jdk.incubator.http.internal.hpack.StringWriter.configure(StringWriter.java:62)
at jdk.incubator.httpclient/jdk.incubator.http.internal.hpack.IndexNameValueWriter.value(IndexNameValueWriter.java:64)
at jdk.incubator.httpclient/jdk.incubator.http.internal.hpack.Encoder.literal(Encoder.java:422)
at jdk.incubator.httpclient/jdk.incubator.http.internal.hpack.Encoder.header(Encoder.java:245)
at jdk.incubator.httpclient/jdk.incubator.http.internal.hpack.Encoder.header(Encoder.java:198)
at jdk.incubator.httpclient/jdk.incubator.http.Http2Connection.encodeHeadersImpl(Http2Connection.java:927)
at jdk.incubator.httpclient/jdk.incubator.http.Http2Connection.encodeHeaders(Http2Connection.java:878)
at jdk.incubator.httpclient/jdk.incubator.http.Http2Connection.encodeHeaders(Http2Connection.java:951)
at jdk.incubator.httpclient/jdk.incubator.http.Http2Connection.sendFrame(Http2Connection.java:984)
at jdk.incubator.httpclient/jdk.incubator.http.Stream.sendHeadersAsync(Stream.java:547)
at jdk.incubator.httpclient/jdk.incubator.http.Exchange.lambda$responseAsyncImpl0$8(Exchange.java:322)
at java.base/java.util.concurrent.CompletableFuture$UniCompose.tryFire(CompletableFuture.java:1072)
at java.base/java.util.concurrent.CompletableFuture.postComplete(CompletableFuture.java:506)
at java.base/java.util.concurrent.CompletableFuture.complete(CompletableFuture.java:2073)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SSLFlowDelegate.setALPN(SSLFlowDelegate.java:164)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SSLFlowDelegate.access$200(SSLFlowDelegate.java:81)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SSLFlowDelegate$Reader.processData(SSLFlowDelegate.java:340)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SSLFlowDelegate$Reader$ReaderDownstreamPusher.run(SSLFlowDelegate.java:215)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler$SynchronizedRestartableTask.run(SequentialScheduler.java:175)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:147)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler$TryEndDeferredCompleter.complete(SequentialScheduler.java:315)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:149)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:198)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:271)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:224)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SSLFlowDelegate$Reader.incoming(SSLFlowDelegate.java:242)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SubscriberWrapper.incomingCaller(SubscriberWrapper.java:388)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SubscriberWrapper.onNext(SubscriberWrapper.java:343)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SubscriberWrapper.onNext(SubscriberWrapper.java:58)
at jdk.incubator.httpclient/jdk.incubator.http.SocketTube$InternalReadPublisher$InternalReadSubscription.read(SocketTube.java:739)
at jdk.incubator.httpclient/jdk.incubator.http.SocketTube$SocketFlowTask.run(SocketTube.java:171)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:198)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:271)
at jdk.incubator.httpclient/jdk.incubator.http.internal.common.SequentialScheduler.runOrSchedule(SequentialScheduler.java:224)
at jdk.incubator.httpclient/jdk.incubator.http.SocketTube$InternalReadPublisher$InternalReadSubscription.signalReadable(SocketTube.java:675)
at jdk.incubator.httpclient/jdk.incubator.http.SocketTube$InternalReadPublisher$ReadEvent.signalEvent(SocketTube.java:829)
at jdk.incubator.httpclient/jdk.incubator.http.SocketTube$SocketFlowEvent.handle(SocketTube.java:243)
at jdk.incubator.httpclient/jdk.incubator.http.HttpClientImpl$SelectorManager.handleEvent(HttpClientImpl.java:769)
at jdk.incubator.httpclient/jdk.incubator.http.HttpClientImpl$SelectorManager.run(HttpClientImpl.java:731)

char=324 means decoded ń from query

When I read stack trace I found jdk.incubator.http.Stream<T> this method in the class:

private void setPseudoHeaderFields() {
    HttpHeadersImpl hdrs = requestPseudoHeaders;
    String method = request.method();
    hdrs.setHeader(":method", method);
    URI uri = request.uri();
    hdrs.setHeader(":scheme", uri.getScheme());
    // TODO: userinfo deprecated. Needs to be removed
    hdrs.setHeader(":authority", uri.getAuthority());
    // TODO: ensure header names beginning with : not in user headers
    String query = uri.getQuery();
    String path = uri.getPath();
    if (path == null || path.isEmpty()) {
        if (method.equalsIgnoreCase("OPTIONS")) {
            path = "*";
        } else {
            path = "/";
        }
    }
    if (query != null) {
        path += "?" + query;
    }
    hdrs.setHeader(":path", path);
}

In this method uri.getQuery() is used which gives us the decoded query and causes the above exception.

When I used uri.getRawQuery() in debug mode (which gave us the encoded query) everything went fine.

My question is: is that a bug or intentional usage? If it is not a bug, how do I avoid the exception?

Answer 1

It is a bug:

java.lang.IllegalArgumentException with jdk.incubator.httpclient when using some UTF-8 characters

Some UTF-8 characters like "š" can't be used with HttpClient. However others like "å" can be.

See: https://bugs.openjdk.java.net/browse/JDK-8201238

---

Java 9/10 HttpClient is incubated. It's not production-ready. It states so very clearly in the package name. As such, it's quite possible that it may contain bugs.

It will be released properly in Java 11 (currently scheduled for release 25th September 2018) as part of JEP 321.