I'm new to Java and to programming in general.

I'm new to Java and to programming in general. I am taking a beginners programming course and when we switched to using an IDE (I'm using NetBeans) I seem to get the error "Illegal start of expression" a lot. I've noticed that on a couple occasions it was fixed by merely deleting and retyping the same line of code again. Now I'm confused by this error because I don't think that its genuinely an illegal start of expression". This occurs even when I copy and paste the codes that our Professor provides for our labs. Is it possible I am missing something?