STSO keeps increasing (lsof)

[Vincent Lam_1]

I've a Java server application running on HP-UX 11.11i (JDK 1.4.2_05). I have been using "lsof" to monitor the file descriptors usage by the application. From the output of lsof, I know that a lot of open file descriptors are of the type "STSO". According to the manpage, it should mean "socket stream". But it isn't consistent with the number of TCP connections reported by "netstat -a".

The number of TCP connections are pretty much constant during peak hours. In non-peak hours, the number has dropped to nearly zero. But the number of open file descriptors of type "STSO" never drops.... it just keep increasing with new users coming in and it never drops when the number of users drops...

What does this mean? does it mean anything unusual with the application?!