400 Bad Request response from Zilla when Using Java HttpClient

[ankitk-me]

Describe the bug
When utilizing Java's HttpRequest and HttpClient classes to send a POST or PUT request to Zilla (http-kafka), a 400 Bad Request response is returned. However, the same endpoint functions correctly when tested with Postman and curl.

To Reproduce
Steps to reproduce the behavior:

1. Start Zilla with the http-kafka configuration.
2. Implement the following Java code to trigger an HTTP request:

HttpRequest httpRequest = HttpRequest.newBuilder(URI.create("http://localhost:%d".formatted(7114)).resolve("/items"))
            .POST(HttpRequest.BodyPublishers.ofString(body))
            .build();
HttpClient client = HttpClient.newHttpClient();
HttpResponse<String> httpResponse = client.send(httpRequest, HttpResponse.BodyHandlers.ofString());

3. Observe that the HTTP response code received is 400 Bad Request.

Expected behavior
The HTTP response code should be 204 No Content instead of 400 Bad Request.