ADDITIONAL SYSTEM INFORMATION :
Linux : "Red Hat Enterprise Linux Server" "7.9 (Maipo)"
Java : jdk-11.0.14


A DESCRIPTION OF THE PROBLEM :
Hello

we faced issues with blocked threads on KeepAliveCache.get

We have a front app which calls a backend app on the same server, sometimes we observe that the front app didn't work, blocked on the calls to the backend. The backend didn't seem receiving the requests…

The local http call from the front App is done with Spring RestTemplate we observe simultaneous blocked threads on different parallelized servers at the same time…
Without exceptions... We used Dynatrace and we can see the stack. I can send to you some screenshots. The app is stuck, impossible to use and after some minutes (15min) it comes back to live.


KeepAliveCache.get
Built-In JRE | sun.net.www.http

HttpClient.New
Built-In JRE | sun.net.www.http

HttpClient.New
Built-In JRE | sun.net.www.http

HttpURLConnection.getNewHttpClient
Built-In JRE | sun.net.www.protocol.http

HttpURLConnection.plainConnect0
Built-In JRE | sun.net.www.protocol.http

HttpURLConnection.plainConnect
Built-In JRE | sun.net.www.protocol.http

HttpURLConnection.connect
Built-In JRE | sun.net.www.protocol.http

SimpleBufferingClientHttpRequest.executeInternal
Built-In Spring | org.springframework.http.client

AbstractBufferingClientHttpRequest.executeInternal
Built-In Spring | org.springframework.http.client

AbstractClientHttpRequest.execute
Built-In Spring | org.springframework.http.client

InterceptingClientHttpRequest$InterceptingRequestExecution.execute
Built-In Spring | org.springframework.http.client

TracingClientHttpRequestInterceptor.intercept
Built-In Spring | org.springframework.cloud.sleuth.instrument.web.mvc

LazyTraceClientHttpRequestInterceptor.intercept
Built-In Spring | org.springframework.cloud.sleuth.instrument.web.client

InterceptingClientHttpRequest$InterceptingRequestExecution.execute
Built-In Spring | org.springframework.http.client

InterceptingClientHttpRequest.executeInternal
Built-In Spring | org.springframework.http.client

AbstractBufferingClientHttpRequest.executeInternal
Built-In Spring | org.springframework.http.client

AbstractClientHttpRequest.execute
Built-In Spring | org.springframework.http.client

RestTemplate.doExecute
Built-In Spring | org.springframework.web.client

RestTemplate.execute
Built-In Spring | org.springframework.web.client

RestTemplate.exchange
Built-In Spring | org.springframework.web.client

HealthCheckController.isGridUpAndRunning
Java | com.bnpparibas.dsibddf.cas.web

here some java parameters :
/apps/JRE11/lastJDK/bin/java -server -Xms3g -Xmx3g -XX:+AlwaysPreTouch -XX:+UseG1GC -XX:+ScavengeBeforeFullGC -XX:+DisableExplicitGC -XX:MaxGCPauseMillis=100 -XX:G1ReservePercent=10 -Dlogging.config=/……/log4j2.xml -jar /…./mywar.war



KeepAliveCache.get
Built-In JRE | sun.net.www.http

HttpClient.New
Built-In JRE | sun.net.www.http

HttpClient.New
Built-In JRE | sun.net.www.http

HttpURLConnection.getNewHttpClient
Built-In JRE | sun.net.www.protocol.http

HttpURLConnection.plainConnect0
Built-In JRE | sun.net.www.protocol.http

HttpURLConnection.plainConnect
Built-In JRE | sun.net.www.protocol.http

HttpURLConnection.connect
Built-In JRE | sun.net.www.protocol.http

SimpleBufferingClientHttpRequest.executeInternal
Built-In Spring | org.springframework.http.client

AbstractBufferingClientHttpRequest.executeInternal
Built-In Spring | org.springframework.http.client

AbstractClientHttpRequest.execute
Built-In Spring | org.springframework.http.client

InterceptingClientHttpRequest$InterceptingRequestExecution.execute
Built-In Spring | org.springframework.http.client

TracingClientHttpRequestInterceptor.intercept
Built-In Spring | org.springframework.cloud.sleuth.instrument.web.mvc

LazyTraceClientHttpRequestInterceptor.intercept
Built-In Spring | org.springframework.cloud.sleuth.instrument.web.client

InterceptingClientHttpRequest$InterceptingRequestExecution.execute
Built-In Spring | org.springframework.http.client

InterceptingClientHttpRequest.executeInternal
Built-In Spring | org.springframework.http.client

AbstractBufferingClientHttpRequest.executeInternal
Built-In Spring | org.springframework.http.client

AbstractClientHttpRequest.execute
Built-In Spring | org.springframework.http.client

RestTemplate.doExecute
Built-In Spring | org.springframework.web.client

RestTemplate.execute
Built-In Spring | org.springframework.web.client

RestTemplate.exchange
Built-In Spring | org.springframework.web.client

HealthCheckController.isGridUpAndRunning
Java | com.bnpparibas.dsibddf.cas.web

here some java parameters :
/apps/JRE11/lastJDK/bin/java -server -Xms3g -Xmx3g -XX:+AlwaysPreTouch -XX:+UseG1GC -XX:+ScavengeBeforeFullGC -XX:+DisableExplicitGC -XX:MaxGCPauseMillis=100 -XX:G1ReservePercent=10 -Dlogging.config=/……/log4j2.xml -jar /…./mywar.war


FREQUENCY : occasionally