Apache Tomcat returns HTTP 502 response error

Hi Guys,

I am having some difficulties on the Tomcat (or the Servlet), can
anyone please help?

Here is how I deploy my application:
Apache <---> Tomcat <---> Servlet

The phenomenon is like this:
1. startup both Apache and Tomcat
2. can access Tomcat via Apache
3. after 2 hours, the Tomcat is not accessable
3.1. can access Apache, and it returns 200 OK response
3.2. can't access Tomcat via Apache, and it returns 502 Bad Gateway
error from the log
3.3. can't access Tomcat via browser, and it returns page not found
error message

Some facts:
1. traffic isn't high at all, I have another controller environment
with the similar setup, but there is no problem at all.
2. both environments are having the same setup/configuration
3. garbarge collection is doing less than 1 second each time
4. no sign of out-of-memory issue

Does anyone encounter this issuse before? I am running out of ideas
though.

Best regards,

tikcireviva.