#And how to use them in Drupal
A popular search engine for Drupal is Apache Solr. Although installation and configuration of Solr can be done almost completely via the Drupal Admin UI, in some cases it can be very instructive to see and understand what data is sent to and from Solr when a search is done from Drupal.
First place to look when using Solr inside Tomcat is the log file of Tomcat, usually /var/log/tomcat6/catalina.out. If this file is not present in this directory on your system use