I'm sure this is a really simple problem, but I'm quite new to Java and I can't figure it out, and am now having trouble thinking of a way of describing it...

OK say you have an application which is a book shop, in the main class file you launch from it it creates a new booklist instance to store all the books in the store.

But now then you want to do some work on this instance but from a different class which wasn't the once that called the construction, ie how can an instance be made global?

Hope this makes sense, I see there inheritance but does this provide access to the current instances/variables or just the methods?

cheers,

David

Instantite an object of the type of class that you want to call and then pass to it's constructor, the reference of the new BookList.

// incomplete code snippet
BookList list = new BookList();
BookListUser = new BookListUser(list);

Cheers

Martyn

Your soloution of your problem depends on many things. Is the modifying object another (model)object, or a GUI object/class. The simplest way to do it is to have a class to that call the construction as you say, and that the same class sends your problem class ( maybe through the constructure ) to the working class. But maybe your problem can be solved through the MVC sofware pattern. Maybe you need an Observer? It's difficult to know with litle information