Steps to reproduce:

1. Go to Preferences > Java > Installed JREs and add as many JREs as possible (you may use 'duplicate' button)
2. Run BrowserSim

Actual result:
Before BrowserSim is started the mouse cursor is changing between waiting and normal state several times. This happens because BrowserSim checks all available JREs for compatibility every time. This should be optimized by caching or at least taking the first compatible JRE without checking the rest.