posted 5 years ago
The catalina.out file is simply the stdout/stderr stream from the Tomcat server app. The standard scripts used to run Tomcat (such as catalina.bat) redirect that stdout to go to TOMCAT_HOME/logs/catalina.out, but non-standard methods of execution may not do so, and instead route it elsewhere, let it default to whatever console Tomcat might have been launched from, or the stdout stream might simply be discarded if it's routed to NULL: or a non-windowed console. This is one of the reasons why webapps should not output to System.out or System.err, since they will go to Tomcat's stdout and stderr streams.
The catalina.out data is quite chatty and starts displaying messages from the moment that Tomcat is first launched, so if you don't see any messages, then consider the reasons I just listed as to possible causes.
In addition to catalina.out, the host subsystem(s) of Tomcat also write logfiles, usually named something like TOMCAT_HOME/logs/xxxxx_localhost.log (or something close enough). These logs sometimes contain critical information when you have a problem but the catalina.out log does not show it. The default location for the host logfiles is part of the Tomcat jvm configuration.
Regular applications are expected to handle their own logging. For example, if a webapp uses log4j, it would typically have a /WEB-INF/classes/log4j.properties or /WEB-INF/classes/log4j.xml config file.
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.