RESTEASY004655: Unable to invoke request: org.apache.http.NoHttpResponseException is thrown when sending a request

Issue

• The exception was shown in server.log. This exception happens rarely, and it doesn't seem to be reproducible. What is the cause?

11:41:07,638 ERROR [org.example.resteasy.client.JaxRsClient] (default task-1) failed to send request: javax.ws.rs.ProcessingException: RESTEASY004655: Unable to invoke request: org.apache.http.NoHttpResponseException: 127.0.0.1:8080 failed to respond
    at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.invoke(ApacheHttpClient4Engine.java:325)
    at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.invoke(ClientInvocation.java:447)
    at org.jboss.resteasy.client.jaxrs.internal.ClientInvocation.invoke(ClientInvocation.java:64)
    at org.jboss.resteasy.client.jaxrs.internal.ClientInvocationBuilder.post(ClientInvocationBuilder.java:227)
    at com.redhat.cee.gss.example.resteasy.client.JaxRsClient.sendRequest(JaxRsClient.java:60)
    at com.redhat.cee.gss.example.resteasy.client.JaxRsClient$Proxy$_$$_WeldClientProxy.sendRequest(Unknown Source)
    at com.redhat.cee.gss.example.resteasy.client.TestServlet.doGet(TestServlet.java:24)
...
Caused by: org.apache.http.NoHttpResponseException: 127.0.0.1:8080 failed to respond
    at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:141)
    at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:56)
    at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:259)
    at org.apache.http.impl.DefaultBHttpClientConnection.receiveResponseHeader(DefaultBHttpClientConnection.java:163)
    at org.apache.http.impl.conn.CPoolProxy.receiveResponseHeader(CPoolProxy.java:157)
    at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:273)
    at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:125)
    at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:272)
    at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:186)
    at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
    at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
    at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:83)
    at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:56)
    at org.jboss.resteasy.client.jaxrs.engines.ApacheHttpClient4Engine.invoke(ApacheHttpClient4Engine.java:320)
    ... 56 more