I recently encountered a problem getting a headache, need help...

System consists of:

Two subsystems, called A, B (each running on a standalone tomcat instance), currently running on the same machine. A invoke B's service via spring httpInvoker(http). B system also invoke other system's services via http.

Symptoms:

1, the system starts to run normally after 10-15 days;

2, the system will run for a period of time after an exception: org.springframework.remoting.RemoteAccessException: Could not access HTTP invoker remote service at [http://xxx.xxx.xxx.xxx/remoting/call]; nested exception is java. net.SocketException: Permission denied: connect

3, when the exception occour, it continues, not only occasional .(it looks like some resources exhausted, but cpu rate < 5%, memory < 15%, network < 5%)

4, A, B when the system call fails, B system via http call to an external service also failed for the same exception.

5, closed two tomcat services, restart, and working properly.

So repeatedly (step 1 - 5), has not found the root reason.

Emvironment:

1. windows 2008 R2
2. tomcat7.0.42 x86_64
3. oralce-jdk-1.7.0_40

Any ideas?