I have Java EE application running on heroku. I need measure load of server CPU. app was runing on my virtual server, I used command top. Can I measure load of CPU on heroku server? I need measure server CPU load when I send a lot of requests by JMeter from my desktop.
You could go for simply installing a Heroku addon designed for application performance monitoring. You can find a list of such addons in the Analytics section here.
I would personally use New Relic for performance monitoring and resource usage. Just call heroku addons:add newrelic in your command line and it installs automatically.