For some reason after installed JMeter, the application icon was not present in Launchpad or in Applications folder. So each time I end up in opening Terminal and run the command $ jmeter & to start JMeter application and I need to keep the terminal open until I finishes my work on JMeter otherwise JMeter also closes when I close Terminal. So I’ve decided to use the power of Apple Script to do this

on run {input, parameters}
	
	set output to do shell script "/usr/local/bin/jmeter > /dev/null 2>&1 &"
	return input
    
end run

Save this Apple Script in to Applications folder and now you can launch it from launchpad.