Server Socket Leaks on stopping Java Processes

Question

I have a strange problem on Windows 2000 Advanced Server with JDK1.5.10. Our application runs on a Tomcat 5.5.12 and is opening 2 server sockets along with Tomcat's own 8080 port. Also we deployed a stand alone application that also opens a server socket. Whenever we stop Tomcat service or our Application service (Windows services) these server sockets are not getting closed. If we use "netstat" to check if any sockets are still open it is NOT showing any sockets.
But when we use "netstat -a" command it is showing entries like
TCP    10.40.1.162:8080    10.40.1.162:0  LISTENING
TCP    10.40.1.162:22222    10.40.1.162:0  LISTENING
TCP    10.40.1.162:33334    10.40.1.162:0  LISTENINGHere 8080 (tomcat), 22222, 33334 are the ports on which the server sockets are opened earlier. We check in Task Manager but there is no java process running. If we try to restart the same java process it is throwing JVM_Bind exception. If we reboot the box the we are able to restart the services. Similar behaviour we observed sometimes on Linux also. I guess some settings in the OS we need to tweak to fix this issue. Can somebody please help me what are those settings for Windows and Linux platforms which reclaims unused server sockets faster??

Answer 1

The state is LISTENING not TIME_WAIT. There is a cleanly closure of sockets provided in the code. It happens to Tomcat's own ports also. If you telnet to these sockets from another box, it is connecting and staying instead of "Connection Failed" error. But in Task Manager or "Services.msc" Console no service or process running! One more observation is that there is heavy load of threads and a huge number of clients socktets were interacting with these sockets just before shutdown.