list all files under directory var, provide a general overview and a link to the full blown document

<geronimo_home>/var/activemq/

<geronimo_home>/var/catalina

A file system directory used by Tomcat Web container as home directory, to hold files common to the entire container. The directory is configured as an attribute named catalinaHome on the GBean for the Tomcat container org.apache.geronimo.tomcat.TomcatContainer. The default value of this attribute is specified as var/catalina.

<geronimo_home>/var/config

A directory with configuration files used by Geronimo at startup.

<geronimo_home>/var/derby/

A directory that holds local Derby database files.

<geronimo_home>/var/log

A directory that holds configuration files and log files during server runtime. look into Apache log4j for the details about definitions in each file, .

<geronimo_home>/var/security

<geronimo_home>/var/shared

A default directories that the Geronimo sharedlib configuration. You can use these directories to easily share .jar files or classes among multiple applications. Place jars or classes in these directories, and declare a dependency in your application deployment plan on the sharedlib configuration. For example:

// Put the following lines in your deployment plan to invoke any classes in <Geronimo_home>/var/shared
...
 <dependencies>
       <dependency>
           <groupId>org.apache.geronimo.configs</groupId>
           <artifactId>sharedlib</artifactId>
       </dependency>
   </dependencies>
...

<geronimo_home>/var/tmp

This temp directory is used by the JVM for temporary file storage. The JVM is configured to use this as its java.io.tmpdir in the geronimo.sh(bat) scripts. Geronimo is configured to use this temporary directory rather than its default for security reasons.The temp directory must exist for Tomcat to work correctly.

<geronimo_home>/var/txlog