Jetty java.util.concurrent.TimeoutException：空闲超时已过期异常

I am running a load test for a Spring Java application's HTTP endpoint with 100 concurrent requests per second for a minute. Even after I stopped the load, the CPU spike remains above 80%. Upon checking, I noticed that 6 QTP threads are occupying more CPU. The application is otherwise idle, with no requests currently coming in. Until the application is restarted, the CPU usage consistently remains above 80%, and those QTP threads are not releasing. In the logs, could see the following exception.

Jetty Version: 9.4.53.v20231009

 2024-04-09T12:58:54.548 Debug usw1rep-000-011.usw1.g2.ghtcc.com RS_usw1 GCTI-153-09900 org.eclipse.jetty.io.IdleTimeout SocketChannelEndPoint@e227f11{l=/10.64.4.114:8080,r=/192.168.255.254:62221,OPEN,fill=-,flush=-,to=30000/30000}{io=0/0,kio=0,kro=1}->HttpConnection@3499b690[p=HttpParser{s=CONTENT,0 of -1},g=HttpGenerator@6fe9bce5{s=START}]=>HttpChannelOverHttp@37de25fe{s=HttpChannelState@402d577d{s=HANDLING rs=BLOCKING os=OPEN is=IDLE awp=false se=false i=true al=0},r=1,c=false/false,a=HANDLING,uri=//usw1rep-000-011.usw1.g2.ghtcc.com:8080/login?user=**%3Cscript%3EJavaScript:alert('cpanel_login_user_xss.nasl')%3B%3C%2Fscript%3E,age=3840243} idle timeout expired
    2024-04-09T12:58:54.548 Debug usw1rep-000-011.usw1.g2.ghtcc.com RS_usw1 GCTI-153-09900 org.eclipse.jetty.io.FillInterest onFail FillInterest@45d598da{null} java.util.concurrent.TimeoutException: Idle timeout expired: 30000/30000 ms
    java.util.concurrent.TimeoutException: Idle timeout expired: 30000/30000 ms
           at org.eclipse.jetty.io.IdleTimeout.checkIdleTimeout(IdleTimeout.java:171)
           at org.eclipse.jetty.io.IdleTimeout.idleCheck(IdleTimeout.java:113)
           at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
           at java.util.concurrent.FutureTask.run(FutureTask.java:264)
           at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
           at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
           at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
           at java.lang.Thread.run(Thread.java:840)

    2024-04-09T12:58:54.549 Debug usw1rep-000-011.usw1.g2.ghtcc.com RS_usw1 GCTI-153-09900 org.eclipse.jetty.io.WriteFlusher ignored: WriteFlusher@53867476{IDLE}->null java.util.concurrent.TimeoutException: Idle timeout expired: 30000/30000 ms
    java.util.concurrent.TimeoutException: Idle timeout expired: 30000/30000 ms
           at org.eclipse.jetty.io.IdleTimeout.checkIdleTimeout(IdleTimeout.java:171)
           at org.eclipse.jetty.io.IdleTimeout.idleCheck(IdleTimeout.java:113)
           at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:539)
           at java.util.concurrent.FutureTask.run(FutureTask.java:264)
           at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:304)
           at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1136)
           at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:635)
           at java.lang.Thread.run(Thread.java:840)

    2024-04-09T12:58:54.549 Debug usw1rep-000-011.usw1.g2.ghtcc.com RS_usw1 GCTI-153-09900 org.eclipse.jetty.io.AbstractEndPoint Ignored idle endpoint SocketChannelEndPoint@e227f11{l=/10.64.4.114:8080,r=/192.168.255.254:62221,OPEN,fill=-,flush=-,to=30000/30000}{io=0/0,kio=0,kro=1}->HttpConnection@3499b690[p=HttpParser{s=CONTENT,0 of -1},g=HttpGenerator@6fe9bce5{s=START}]=>HttpChannelOverHttp@37de25fe{s=HttpChannelState@402d577d{s=HANDLING rs=BLOCKING os=OPEN is=IDLE awp=false se=false i=true al=0},r=1,c=false/false,a=HANDLING,uri=//usw1rep-000-011.usw1.g2.ghtcc.com:8080/login?user=**%3Cscript%3EJavaScript:alert('cpanel_login_user_xss.nasl')%3B%3C%2Fscript%3E,age=3840244}