What is JMeter ?
The Apache JMeter is completely Java open source software. It was first developed by Stefano Mazzocchi who was working for Apache Software Foundation, designed to load test functional behavior and measure performance. You can use JMeter to measure the performance of variety of services or web applications. Performance testing means testing a web application against concurrent & multiple user traffic and heavy loads. JMeter originally is used for testing FTP application or Web Application. These days it is used for database server test, functional test etc.
How does JMeter work?
JMeter imitates a group of users. They will send requests to a targeted server and return statistics information of target server through graphical diagrams & tables.
Advantages of JMeter: Some of the advantages of JMeter are as follows:
1. Open Source License: It is a free tool and it also helps developers by allowing them to use the source code for the development.
2. Friendly GUI: User takes less time to get familiar with it and it is really easy to use.
3. Platform Independent: JMeter is purely and completely a java desktop application which can also run on multiple platforms.
4. Full Multi-threading Framework: It allows concurrent and synchronized sampling of different functions by a different thread group.
5. Visualize Test Results: Test results can be shown in different formats like table, tree, chart and log file.
6. Easy Installation: One of the advantages of JMeter is that there is no need of installation. You just need to put JMeter source files in a location on your machine and run jmeter.bat file from bin folder of JMeter.
7. Highly Extensible: User can write his/her own tests. JMeter also supports visualization plugins which allows user to extend his/her testing.
8. Multiple Testing Strategy: Jmeter supports many testing techniques like load testing, Distributed testing and functional testing.
9. Simulation: Jmeter can simulate multiple users with coexisting threads and create a heavy load against web application under test.
10. Support Multiple Protocols: JMeter evaluates database server performance and supports web application testing. Performance of all basic protocols such as FTP, JMS, SOAP, LDAP, JDBC and HTTP can be evaluated through it.
11. Record & Playback- Record the user movement on the browser and imitate them in web application using JMeter.
12. Script Test: JMeter can be combined with Selenium & bean shell for automated testing.
How to View JMeter Test Results in Real-time?
The customary way to use JMeter is in Non-GUI mode (CLI). By running in CLI mode, users save resources and ensure their test results are reliable. Using the JMeter, GUI is meant only for development, debugging and test recording.
The Problem - JMeter Limits Viewing Test Results in Real-Time: Though, running JMeter in CLI mode may bound users who want to understand what is going on in their test in real-time, as CLI mode stops incorporating listeners during the test run. Any listener you used to have in your test plan were probably Graphical User Interface mode specific and don’t send anything to non-GUI mode.
Nowadays, when users want to understand what is occurring in their test, they have to wait for the test to finish running. Then they take the sample.jtl file that their load test produced, open the JMeter GUI and add their preferred listener to the test plan. They can then load the sample.jtl file into the Listener and see the graph/reports.