ADDITIONAL SYSTEM INFORMATION :
Windows 11
java 25.0.1 2025-10-21 LTS
Java(TM) SE Runtime Environment (build 25.0.1+8-LTS-27)
Java HotSpot(TM) 64-Bit Server VM (build 25.0.1+8-LTS-27, mixed mode, sharing)


A DESCRIPTION OF THE PROBLEM :
When using java.net.http.HttpClient on Windows, sending an HTTP POST through a proxy that requires authentication results in the error:

HTTP/1.1 header parser received no bytes

This occurs if no credentials or incorrect credentials are supplied. The same error can occur intermittently even when credential are supplied.

On Linux, the same scenario correctly reports a credential-related error (e.g., No credentials provided).


STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. In WSL, install tinyproxy (https://tinyproxy.github.io/) and configure it to require basic authentication:
tinyproxy.conf:
Port 8866
Listen 127.0.0.1
Timeout 600
Allow 127.0.0.1
BasicAuth abc xyz
LogLevel Info
2. On WSL, Start the proxy:
$ tinyproxy -d -c ./tinyproxy.conf
NOTICE [6068]: Initializing tinyproxy ...
NOTICE [6068]: Reloading config file
INFO [6068]: Added address [127.0.0.1] to listen addresses.
INFO [6068]: Added basic auth user : abc
NOTICE [6068]: Reloading config file finished
INFO [6068]: listen_sock called with addr = '127.0.0.1'
INFO [6068]: trying to listen on host[127.0.0.1], family[2], socktype[1], proto[6]
INFO [6068]: listening on fd [3]
INFO [6068]: Not running as root, so not changing UID/GID.
INFO [6068]: Setting the various signals.
INFO [6068]: Starting main loop. Accepting connections.
3. On Windows, run the Java program (ProxyPost.java) that sends a POST request via this proxy but provides wrong credentials:
> java ProxyPost.java
Exception in thread "main" java.io.IOException: HTTP/1.1 header parser received no bytes
...

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
An authentication error indicating invalid or missing credentials (as seen on Linux):

$ java ProxyPost.java
Exception in thread "main" java.io.IOException: No credentials provided
        at java.net.http/jdk.internal.net.http.HttpClientImpl.send(HttpClientImpl.java:938)
        at java.net.http/jdk.internal.net.http.HttpClientFacade.send(HttpClientFacade.java:133)
        at ProxyPost.main(ProxyPost.java:41)
Caused by: java.io.IOException: No credentials provided
        at java.net.http/jdk.internal.net.http.AuthenticationFilter.response(AuthenticationFilter.java:319)
...
ACTUAL -
The program throws:

Exception in thread "main" java.io.IOException: HTTP/1.1 header parser received no bytes
at java.net.http/jdk.internal.net.http.HttpClientImpl.send(HttpClientImpl.java:938)
at java.net.http/jdk.internal.net.http.HttpClientFacade.send(HttpClientFacade.java:133)
at ProxyPost.main(ProxyPost.java:41)
Caused by: java.io.IOException: HTTP/1.1 header parser received no bytes
at java.net.http/jdk.internal.net.http.common.Utils.wrapWithExtraDetail(Utils.java:456)
at java.net.http/jdk.internal.net.http.Http1Response$HeadersReader.onReadError(Http1Response.java:591)
at java.net.http/jdk.internal.net.http.Http1AsyncReceiver.checkForErrors(Http1AsyncReceiver.java:304)
at java.net.http/jdk.internal.net.http.Http1AsyncReceiver.flush(Http1AsyncReceiver.java:270)
at java.net.http/jdk.internal.net.http.common.SequentialScheduler$LockingRestartableTask.run(SequentialScheduler.java:182)
...

---------- BEGIN SOURCE ----------
import java.net.InetSocketAddress;
import java.net.PasswordAuthentication;
import java.net.ProxySelector;
import java.net.URI;
import java.net.Authenticator;
import java.net.http.HttpClient;
import java.net.http.HttpRequest;
import java.net.http.HttpResponse;

public class ProxyPost {
  public static void main(String[] args) throws Exception {

    HttpClient client = HttpClient.newBuilder()
      .proxy(ProxySelector.of(new InetSocketAddress("localhost", 8866)))
      .authenticator(new Authenticator() {
          @Override
            protected PasswordAuthentication getPasswordAuthentication() {
            if (getRequestorType() == RequestorType.PROXY) {
              return new PasswordAuthentication(
                                                "wrong",
                                                "cred".toCharArray()
                                                );
            }
            return null;
          }
        })
      .build();

    HttpRequest request = HttpRequest.newBuilder()
      .uri(URI.create("http://httpbin.org/post"))
      .header("Content-Type", "text/plain; charset=UTF-8")
      .POST(
            HttpRequest.BodyPublishers.ofString("some body text")
            )
      .build();

    // Thread.sleep(2000);

    HttpResponse<String> response =
      client.send(request, HttpResponse.BodyHandlers.ofString());

    System.out.println("Status: " + response.statusCode());
    System.out.println("Response:");
    System.out.println(response.body());
  }
}

---------- END SOURCE ----------