JMeter - Load and Performance tester

JMeter is a pure Java desktop application designed to load test functional behavior and measure performance. It may be used to test performance both on static and dynamic resources (files, Servlets, Perl scripts, Java Objects, Data Bases and Queries, FTP Servers and more). It can be used to simulate a heavy load on a server, network or object to test its strength or to analyze overall performance under different load types.

It could do performance test for Web application, Web services, Database, LDAP, JMS, Mail. It produces graphical analysis of test report. Test results could be cached offline. Data analysis and visualization plugins allow great extensibility.