So post your code so we know what the heck you are talking about.

And if you do not know the basic concepts of object oriented programming or Java for that matter, what are you doing writing applications with them ???

First learn the concepts of the language, the methodology of OOP so that you have a strong foundation and then use the "learn as you go" approach with the rest of the cosmetic stuff (Collections API, etc).

1. start off with some lineair developing in Java, to get to know the syntaxis
2. learn to think in an OO way, and learn how to code that in Java
3. now you can think about writing such applications

if (above40)
reject cuz you're too old


There you go.

well really the purpose of OOP is to make you learn easier. so what you do to start is lay down the steps that you can accomplish it without code but based in java.
like are you going to enter a number form the keyboard ?
if so assing lets say "input" and if input >40 " S.o.p('TOO OLD")
if input <40 S.o.p("GET IN")
unless you want to store your input .
If you are completely new to java and dont even know to write "hello worl"
well goodbye

@notuserfriendly: What you posted really has nothing to do with OOP. And the purpose of OOP is to manage organizational and behavioral complexity in code design - not "learning easier". You may want to do a bit more reading on the subject:
http://en.wikipedia.org/wiki/Object-...ed_programming