JMeter's classpath

Since JMeter is 100 percent pure Java, it comes packed with functionalities to get most of the test cases scripted. However, there might come a time when you need to pull in a functionality provided by a third-party library, or one developed by yourself, which is not present by default. As such, JMeter provides two directories where such third-party libraries can be placed to be auto discovered on its classpath:

• JMETER_HOME/lib: This is used for utility JARs.
• JMETER_HOME/lib/ext: This is used for JMeter components and add-ons. All custom-developed JMeter components should be placed in the lib/ext folder, while third-party libraries (JAR files) should reside in the lib folder.