Hi.
Your three problems are actually one.
See, when you write a public class in Java, you are supposed to put it in
a file that has the same name as that public class.
So, if you want to write a class named 'Nimo' (which is a very nice name) -
you should put it in a file named Nimo.java.
You do not give the name of the file that you put your code in, but you named your class 'Excercise 9.1' - which you can't really do. What you
get is that you are trying to declare a class named Excercise, and then
the compiler expects something - perhaps a '{' character, but it gets
the '9.1'
string instead, which it can not parse to anything that makes sense at these settings.
You probably want to name your class something like Excercise9_1 or simply Excercise or whatever. Just make sure that you put it in a file that has the correct name.
I saw that someone told you about Bruce Eckel's 'Thinking in Java' - doesn't matter what correspondence course you're taking - this book can make your study a lot easier. You can download it from the web (I think from
www.bruceeckel.com, but if not - a little google-search will help)
Nimo.