Does WAR updates JSP timestamps on Tomcat?

Question

I answered another forum post with an answer that I'm not certain is correct.
For the sake of argument, if you have a Tomcat-based website up and running, and Tomcat has compiled the JSPs on that site, subsequent changes to any included files are not recognized unless Tomcat is forced to recompile the parent JSP. This is usually by updating the timestamp on the parent.
It is possible to deploy a WAR file to a live copy of Tomcat, that is, you don't need to restart it.
If the WAR file has say, hello.jsp and hello.jsp has the same timestamp as the currently used version, does deploying the WAR file cause Tomcat to think the new hello.jsp is a change to the original, and therefore must be recompiled?
I realize this is actually fairly easy to test, but I'm hoping someone knows the answer offhand?

Answer 1

On deploying the WAR Tomcat unpacks the WAR, thus when accessing the JSP it does not see that the actual JSP file has been replaced (as you stated the timestamp on that is identical).
Therefore there are only 2 scenarios in which Tomcat would recompile the JSP on call:
1) when/if Tomcat is configured to discard compiled JSPs on reloading a web application (this might be theoretical. I don't know if Tomcat offers that option)
2) when/if Tomcat discards compiled JSPs when redeploying a webapp.
This of course changes your question to: does Tomcat delete compiled JSPs when redeploying a webapp :)