As the summary says.

Example:
        HttpClient client = HttpClient.newBuilder()
                .sslContext(sslContext)
                .sslParameters(new SSLParameters())
                .build();

The above HttpClient will not use Http2 or Http3. That's because the tests in HttpConnection#hasRequiredHTTP2TLSVersion and HttpQuicConnection#hasRequiredHTTP3TLSVersion return false when no protocols are configured.

Workaround: when setting SSLParameters, start with SSLContext.getDefaultSSLParameters(), instead of starting from newly constructed SSLParameters.

Originally reported by Christoph Läubrich.