What can I do with it?
Apache JMeter 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. You can use it to make a graphical analysis of performance or to test your server/script/object behavior under heavy concurrent load.
What does it do?
Apache JMeter features include:
* Can load and performance test many different server types:
1.Web - HTTP, HTTPS
2.SOAP
3.Database via JDBC
4.LDAP
5.JMS
6.Mail - POP3(S) and IMAP(S)
* Complete portability and 100% Java purity .
* Full multithreading framework allows concurrent sampling by many threads and simultaneous sampling of different functions by seperate thread groups.
* Careful GUI design allows faster operation and more precise timings.
* Caching and offline analysis/replaying of test results.
* Highly Extensible.
Pluggable Samplers allow unlimited testing capabilities.
Several load statistics may be choosen with pluggable timers .
Data analysis and visualization plugins allow great extendibility as well as personalization.
Functions can be used to provide dynamic input to a test or provide data manipulation.
Scriptable Samplers (BeanShell is fully supported; and there is a sampler which supports BSF-compatible languages)
JMeter is not a browser
JMeter is not a browser. As far as web-services and remote services are concerned, JMeter looks like a browser (or rather, multiple browsers); however JMeter does not perform all the actions supported by browsers. In particular, JMeter does not execute the Javascript found in HTML pages. Nor does it render the HTML pages as a browser does (it`s possible to view the response as HTML etc, but the timings are not included in any samples, and only one sample in one thread is ever viewed at a time).
Source:
http://jakarta.apache.org/jmeter/