Druid is an open-source database connection pool written in Java. Druid is able to provide an extensive number of powerful monitoring functionalities for database connection. Druid has been deployed to the maven central repository. Druid provides a monitoring feature that can be implemented through filter-chain. It also comes with WallFilter, that is based on the SQL semantic analysis to protect from SQL injection attacks.
Hyperic is application monitoring and performance management for virtual, physical, and cloud infrastructures. Auto-discover resources of 75+ technologies, including vSphere, and collect availability, performance, utilization, and throughput metrics.
Monitoring tool with support to Websites, RSS, Webservices and Databases. Has notifications by email and RSS and you can access metrics like availability, latency and load time by a web-based GUI. Runs standalone with an embedded HTTP server.