logstash is a tool for managing events and logs. You can use it to collect logs, parse them, and store them for later use (like, for searching). Speaking of searching, logstash comes with a web interface for searching and drilling into all of your logs.

log4perl.appender.LOG1.filename = /var/log/mylog.log

adds log4j loggers for various levels of info about JDBC operations

"Nimrod is a metrics server purely based on log processing: hence, it doesn't affect the way you write your applications, nor has it any side effect on them."

real-time log monitoring system based on Node.js providing data visualization within web browsers