The location for deployed applications is not engraved in granite. There's a standard location for deployments for Tomcat, though this can be overridden in the server.xml file, and if I remember aright, it's CATLINA_HOME/conf/Catalina/localhost (or CATALINA_BASE, I can't remember which is which). You can deploy Tomcat applications by dropping xml files in that directory. These xml files consist of <Context> elements as defined in the Tomcat docs. Oh well, how about I read the docs:
http://tomcat.apache.org/tomcat-5.5-doc/deployer-howto.html The docBase for a Context Descriptor can be any locally-addressable filesystem path, so it's quite valid to use something like "ECLIPSE_HOME/workspace/project1/build/webapp1" to point to the exploded WAR.
Actual behavior varies from release to release, but Tomcat 5 copies the application WAR from the indicates docBase to the CATALINA_HOME/webapps directory (and explodes it if it's a WAR file and not a directory). Tomcat4 could handle unexploded WARs, but it didn't have the Catalina/localhost deployment directory. The context Descriptors were placed in CATALINA_HOME/webapps, where they had an unfortunate habit of colliding with other files.
The secret of how to be miserable is to constantly expect things are going to happen the way that they are "supposed" to happen.
You can have faith, which carries the understanding that you may be disappointed. Then there's being a willfully-blind idiot, which virtually guarantees it.