[eclipse-clp-users] Problem of Collections.EMPTY_LIST.

hello, everyone!
I am meeting some problem when I am using ECLiPSe to solving problem.
The problem is I can't distinguish any arg of CompoundTerm is that a list or a empty list?
I tried many ways to comparing, but I am failed at all.
Which way I should used correctly?
I wrote this line(of course, I run compile and query in eclipse.rpc first),
" if((((CompoundTerm)(CompoundTerm)result.arg(i)).arg(j)==(Collections.EMPTY_LIST))) ",
and it's always return true.
Why???
Can you give me some hint???
                                                                                                                Best regards.