Java Simon - Simple Monitoring API
Java Simon is a simple monitoring API that allows you to follow and better understand your application. Monitors (familiarly called Simons) are placed directly into your code and you can choose whether you want to count something or measure time/duration.
Current version 3.0 (released on October 11th, 2011) provides basic monitor functionality, extensibility via Callbacks, JMX and Spring integration tools (AOP based, AspectJ is WIP) and also easy to use JDBC4 proxy driver that measures JDBC performance and can log all statements too. Version requires Java SE 6 or higher.