title: Some Spring WebSocket Sessions never disconnect
body: <p>I have a websocket solution for duplex communication between mobile apps and a java backend system. I am using Spring WebSockets, with STOMP. I have implemented a ping-pong solution to keep websockets open longer than 30 seconds because I need longer sessions than that. Sometimes I get these errors in the logs, which seem to come from <a href="http://www.massapi.com/source/github/40/71/407140336/spring-websocket/src/main/java/org/springframework/web/socket/messaging/SubProtocolWebSocketHandler.java.html" rel="nofollow">checkSession() in Spring's SubProtocolWebSocketHandler</a>.</p>
  
  <p>server.log: 07:38:41,090 ERROR [org.springframework.web.socket.messaging.SubProtocolWebSocketHandler] (ajp-http-executor-threads - 14526905) No messages received after 60205 ms. Closing StandardWebSocketSession[id=214a10, uri=/base/api/websocket].</p>
  
  <p>They are not very frequent, but happens every day and the time of 60 seconds seem appropriate since it's hardcoded into the Spring class mentioned above. But then after running the application for a while I start getting large amounts of these really long-lived 'timeouts':</p>
  
  <p>server.log: 00:09:25,961 ERROR [org.springframework.web.socket.messaging.SubProtocolWebSocketHandler] (ajp-http-executor-threads - 14199679) No messages received after 208049286 ms. Closing StandardWebSocketSession[id=11a9d9, uri=/base/api/websocket].</p>
  
  <p>And at about this time the application starts experiencing problems.</p>
  
  <p>I've been trying to search for this behavior but havn't found it anywhere on the web. Has anyone seen this problem before, know a solution, or can explain it to me?</p>