How does Tomcat 6 know to automatically redeploy an application?

[patrick flaherty]

I shut Tomcat down and then thought I could remove an application by simply deleting its directory under the webapps directory.

However when I restarted Tomcat it automatically redeployed (installed) the application.

The application build is on the same machine and under my d:\"eclipse workspace" directory (this is Windows 7). I grepped the whole of the tomcat installation to see if I could find this value anyway (that is, where Tomcat would find the files to redeploy) but didn't come up with anything.

How does Tomcat know where and how to find and redeploy an application? Is there a file that represents the central repository for a Tomcat installation for what applications it should find? I looked through the files in the %TOMCAT_HOME%\conf and didn't find what I was looking for there either.

thanks - pat

[patrick flaherty]

Perhaps I was wrong and Tomcat doesn't have a central listing of applications - perhaps it just bases itself off of what it finds in webapps.

I removed my application again by simply deleting the its directory and contents from the file system. When I reran Tomcat it did not redeploy.

So I deployed it from using http://localhost:8080/manager/html using the Tomcat application root directory name and the project's WAR file from its build location under Eclipse and that worked.

Anyone know how to deploy to Tomcat 6 from Eclipse 3.6? Its an Eclipse maven project using m2e. I've looked around inside Eclipse and have yet to figure out how to successfully use Eclipse to deploy. 'Build', 'package', etc: yes. But the maven install puts the both the WAR and extracted WAR into a local Eclipse directory. There must be some way of telling Eclipse where the Tomcat install directory is.

[Tim Holloway]

Nope. Tomcat doesn't have a central registry of webapps. What it does is scan the webapp contexts when it starts up. And, by default, periodically thereafter. The contexts that are scanned are as follows:

1. The TOMCAT_HOME/webapps directory. If an exploded WAR is found, Tomcat attempts to deploy it. If an unexploded WAR is found AND there is no corresponding exploded WAR, Tomcat will explode it and deploy it (assuming default server config).

2. The webapp context directory. This is typically TOMCAT_HOME/conf/catalina/localhost. Contexts found there will be deployed.

3. The Tomcat server.xml file. However, this is no longer a recommended place to put webapp Context definitions and hasn't been for a long, long time.

I have probably missed a place or 2. And, in case anyone's wondering, "TOMCAT_HOME" is the cop-out shorthand I use when referring to the Tomcat server's root directory and am too lazy to lookup whether it should be the CATALINA_HOME location or the CATALINA_BASE location, since usually they're the same place.

[patrick flaherty]

thanks Tim - that's helpful.

I now have it sorted out and working.