The phrase is taken from the
book of Joshep Heller by the same,
name Catch 22. A Catch 22 is a logical
paradox (confusing state) in which a person requires
something that can only be obtained
by not being in that situation. Hence its
acquision (obtention) is impossible.
It is usually used with regard to rules,
regulatioins and similar situations in which
the person is aware that he/she will
finally become victim.
Its a very interesting
book. Very funny. If available
read if any one wishes. I read