NullPointerException in jdk.incubator.http.internal.hpack.HeaderTable.Table

[Андрей Турбанов]

Hello
I'm trying to new use new shiny httpclient from JDK10. Code is pretty
simple. I use synchronous HTTP call form multiple threads:

private final HttpClient httpClient = HttpClient.newBuilder()
        .executor(Utils.newFixedThreadPoolExecutor(1, "HttpClient"))
        .build();
private JsonObject useHttpClient(URL url, String params) throws Exception {
    HttpRequest req = HttpRequest.newBuilder()
            .uri(url.toURI())
            .setHeader("Connection", "keep-alive")
            .setHeader("Accept-Encoding", "gzip")
            .timeout(timeout)
            .POST(HttpRequest.BodyPublisher.fromString(params))
            .build();
    HttpResponse<InputStream> response = httpClient.send(req,
HttpResponse.BodyHandler.asInputStream());
    if (response.statusCode() != 200) {
        throw new IOException("Server returned " + response.statusCode());
    }
    String encoding =
response.headers().firstValue("content-encoding").orElse("");
    return parseResponseStream(encoding, response.body());}

<https://stackoverflow.com/questions/49587380/nullpointerexception-in-jdk-incubator-httpclient#>

Sometimes I get NPEs:

java.lang.NullPointerException: null
at 
jdk.incubator.http.internal.hpack.HeaderTable$Table.remove(HeaderTable.java:455)
~[jdk.incubator.httpclient:?]
at 
jdk.incubator.http.internal.hpack.HeaderTable.evictEntry(HeaderTable.java:264)
~[jdk.incubator.httpclient:?]
at jdk.incubator.http.internal.hpack.HeaderTable.put(HeaderTable.java:233)
~[jdk.incubator.httpclient:?]
at jdk.incubator.http.internal.hpack.HeaderTable.put(HeaderTable.java:215)
~[jdk.incubator.httpclient:?]
at 
jdk.incubator.http.internal.hpack.Decoder.resumeLiteralWithIndexing(Decoder.java:464)
~[jdk.incubator.httpclient:?]
at jdk.incubator.http.internal.hpack.Decoder.proceed(Decoder.java:268)
~[jdk.incubator.httpclient:?]
at jdk.incubator.http.internal.hpack.Decoder.decode(Decoder.java:246)
~[jdk.incubator.httpclient:?]
at jdk.incubator.http.Http2Connection.decodeHeaders(Http2Connection.java:471)
~[jdk.incubator.httpclient:?]
at jdk.incubator.http.Http2Connection.processFrame(Http2Connection.java:635)
~[jdk.incubator.httpclient:?]
at 
jdk.incubator.http.internal.frame.FramesDecoder.decode(FramesDecoder.java:156)
~[jdk.incubator.httpclient:?]
at 
jdk.incubator.http.Http2Connection$FramesController.processReceivedData(Http2Connection.java:195)
~[jdk.incubator.httpclient:?]
at jdk.incubator.http.Http2Connection.asyncReceive(Http2Connection.java:528)
~[jdk.incubator.httpclient:?]
at 
jdk.incubator.http.Http2Connection$Http2TubeSubscriber.processQueue(Http2Connection.java:1054)
~[jdk.incubator.httpclient:?]
at 
jdk.incubator.http.internal.common.SequentialScheduler$SynchronizedRestartableTask.run(SequentialScheduler.java:175)
~[jdk.incubator.httpclient:?]
at 
jdk.incubator.http.internal.common.SequentialScheduler$CompleteRestartableTask.run(SequentialScheduler.java:147)
~[jdk.incubator.httpclient:?]
at 
jdk.incubator.http.internal.common.SequentialScheduler$SchedulableTask.run(SequentialScheduler.java:198)
~[jdk.incubator.httpclient:?]
at 
java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1135)
[?:?]

Are there any problem in my code? What can be reason for this exception?

C:\Program Files\Java\jdk-10\bin>java -version
java version "10" 2018-03-20Java(TM) SE Runtime Environment 18.3
(build 10+46)Java HotSpot(TM) 64-Bit Server VM 18.3 (build 10+46,
mixed mode)



Andrey Turbanov