SpringBoot The number of TCP connections is increasing.

Spring Boot Version: 2.3.1 or the dependency netty version: 4.1.50 When using spring cloud gateway, it happens. I think this bug's root cause is not Gateway, when using a sample Webclient to retrive a remote restful API, this happens.

The test code: @RestController @Slf4j public class WebClientController {

@Autowired
private WebClient.Builder webClientBuilder;

@PostMapping(value = "/wb")
public Mono<String> wbTest(@PathVariable(required = false) String action) {
    return webClientBuilder.build().get().uri("http://remoteIP:remotePort/privaters/jwks/pub")
            .retrieve()
            .bodyToMono(String.class);
}

} After a few requst, using lsof -p XXX to check, then shows scokets leaked!

java 10823 ircp 32u sock 0,7 0t0 154700740 protocol: TCP java 10823 ircp 33u sock 0,7 0t0 154701211 protocol: TCP java 10823 ircp 34u sock 0,7 0t0 154700776 protocol: TCP java 10823 ircp 35u sock 0,7 0t0 154700777 protocol: TCP java 10823 ircp 36u sock 0,7 0t0 154700778 protocol: TCP java 10823 ircp 37u sock 0,7 0t0 154701301 protocol: TCP java 10823 ircp 38u sock 0,7 0t0 154701304 protocol: TCP java 10823 ircp 39u sock 0,7 0t0 154701307 protocol: TCP java 10823 ircp 40u sock 0,7 0t0 154701837 protocol: TCP

I guess this bug should be caused by Spring Boot.

Comment From: wilkinsona

Thanks for the report. This looks like a duplicate of #21923.