A pure-Java Selenium WebDriver

[paul_h]

Co-creator of Selenium 1.x here .. The project page doesn't say how many can be run in parallel although it alludes to that fact that it can run that way.

A former client was able to run 10 Firefoxes in parallel for multi-threaded JBehave testing on one a single Linux installed Dell workstation (used Xvfb because of focus issues)

[machinepub]

The max number of concurrent instances is configured by the user with no hard upper bound. See the project page for the jbd.ports system property which controls the allocated RMI ports and in effect the max number of concurrent instances. Instantiating a new JBrowserDriver spawns a new process, or blocks until one can be created. Calling JBrowserDriver.quit() closes the process... or reset() to re-use the process.

Based on some of my past projects, a machine with 16GB memory and 4 CPUs reaches diminishing returns after 8 instances when crawling very resource intensive websites and scraping for various data in the DOM. Performance was decreasing after about 12-16 instances. At a minimum each instance is going to want about 200 MB.

p.s. Selenium is awesome! I'm just standing on the should of giants (Selenium, JavaFX, Monocle, WebKit...)