Worksnaps client on Mac OS X uses Java run-time, so you must install Java first on your Mac OS X. 

If you have not installed Java and run Worksnaps client, it will pop up the following message -- 

"To open 'Worksnaps Client', you need a Java SE 6 runtime. Would you like to install one now?" dialog. Please click Install button to install it.(Figure 1).

Figure 1