Need to get/read executable permission from existing file in Java 1.5 (not grater)

Hi. I want to get/read executable permission (x) from existing file, but I'cant find solution in Java 1.5.
I know, that in Java 1.6 can invoke method of File class: f.canExecute(), but this method is existing since Java 1.6.
Can you help me?

Make a native call (or a Runtime.exec)?
Since you seem to be working on a *nix then portability isn't that much of a problem.

probably You have right.
Thanks for help.

L.J.