Apache JMeter is an Apache project that can be used as a load testing tool for analyzing and measuring the performance of a variety of services, with a focus on web applications.
JMeter can be used as a unit test tool for JDBC database connections, FTP, LDAP, Webservices, JMS, HTTP, generic TCP connections and OS Native processes. JMeter can also be configured as a monitor, although this is typically considered an ad-hoc solution in lieu of advanced monitoring solutions.