Out of all the stuff in the SCJP exam the only stuff I've rarely encountered are multithreading and assertions.
Both of those are directly related to my area of work, which is mainly web applications.
Assertions there are not something you want, as triggering one would crash the application server (oops...).
Servlets and JSPs are automatically multithreaded so there's little use for threads either (except the occasional
thread being started to do some long running background task the client doesn't have to wait for).
In my
SCJD assignment, I've used both however (though not many assertions, I might need to add some more at places).
And that one's another amalgamation of things you could encounter in your daily work, though for me it means mainly things I don't encounter in my daily work again because I do mainly serverside stuff and the SCJD is mainly clientside stuff.