Authors Apache JMeter `.jmx` test plans (Thread Groups + HTTP samplers + assertions + listeners) in the JMeter GUI, runs them headlessly via `jmeter -n -t plan.jmx -l results.jtl`, generates an HTML dashboard with `-e -o`, and gates CI on JTL parsing. Use when the project has an existing JMeter investment, needs JVM-native load tooling, or works in domains with strong JMeter community support (banking, telecom, enterprise).