[GridSim-users] error

[amani <ros...@ya...>]

hi

i finished downloading gridsim on ubuntu 12.04 and ran ezample 1,2 .. but exaple 6 give me the following error 

Note: example06/Example6.java uses unchecked or unsafe operations.
Note: Recompile with -Xlint:unchecked for details.

why what can i do?
Regards
Amani