Apache JMeter is an open source Java desktop application for load testing. It is available for download from the Apache website (http://jmeter.apache.org). In the examples of this book, we'll be using Version 2.10.
JMeter was originally designed for testing web applications but has since expanded to support other protocols. The supported protocols that may be of interest for a Java EE environment are as follows:
HTTP(S)
SOAP
FTP
JDBC
JMS
SMTP(S)
POP3(S)
IMAP(S)
The extensible core of JMeter provides a functionality that simplifies the process of supporting new protocols and operations. JMeter uses multithreading to produce load. This is used when simulating multiple callers. Besides call generation, it also provides functionalities for response validations, data analysis, and an easy-to-use GUI.