Understand the default Apache Tomcat configuration
The main Apache Tomcat configuration file is at installdir/apache-tomcat/conf/server.xml.
Once Apache Tomcat starts, it will create several log files in the installdir/apache-tomcat/logs directory. The main log file is the catalina.out file where you can find error messages.
For more information on logging in Apache Tomcat, refer to the logging FAQ in the Apache Tomcat wiki.