I didn't really understand your request. Can you please post some code to demonstrate the problem? What's wrong with the approach of using JTabbedPane, if you want a "button that acts like a tab"?
ItDoesntWorkIsUseless (<- click), please be more specific. The general principle proposed above should do the trick. Though, I would suggest you never have more than one JFrame per application; use JDialog instead.
Factory method pattern is a good place to start, also with some examples and comments on them. I am sure that you can find a lot of other resources by searching the internet a bit.
Keep in mind that the division operator denotes integer division if both operands are integers, and floating-point division otherwise. Yours is the first case - both of your operands are integers (e.g. 1/2 = 0 by integer division), hence the results you get.
In order to get the most out of this community you need to ShowSomeEffort and TellTheDetails. However, you cannot expect to be provided with full solution since this forum is NotACodeMill.
If they are all in the same package, there won't be a problem with that; otherwise you would use import statement for other classes.
Though it's a question for another topic, I would suggest you read a Java tutorial, specifically the Packages section, to get more details. I'm posting from phone now so I can't provide a link, but if you Google for it you'll find it easily.
