A DESCRIPTION OF THE PROBLEM :
The setup is
- nginx as reverse proxy with SSL and http/2
- REST API behind nginx

The application performs many requests to that API using HttpClient from JDK, which automatically detects http/2 via ALPN.
nginx closes connection after 1000 requests, configurable with the keepalive_requests directive (applies for both http/1.1 persistent connections and http/2).

If specifically configuring the client as http/1.1 then everything works.

Also happens in java 17.

The stacktrace is

java.io.IOException: /172.30.30.7:51892: GOAWAY received
at java.net.http/jdk.internal.net.http.Http2Connection.handleGoAway(Http2Connection.java:1011)
at java.net.http/jdk.internal.net.http.Http2Connection.handleConnectionFrame(Http2Connection.java:876)
at java.net.http/jdk.internal.net.http.Http2Connection.processFrame(Http2Connection.java:751)
at java.net.http/jdk.internal.net.http.frame.FramesDecoder.decode(FramesDecoder.java:155)
at java.net.http/jdk.internal.net.http.Http2Connection$FramesController.processReceivedData(Http2Connection.java:232)
at java.net.http/jdk.internal.net.http.Http2Connection.asyncReceive(Http2Connection.java:677)
at java.net.http/jdk.internal.net.http.Http2Connection$Http2TubeSubscriber.processQueue(Http2Connection.java:1313)

All suggesting to either downgrade to http/1.1 or change the client.