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Java Garage by Eben Hewitt

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What Is an Abstract Class?

You cannot instantiate an abstract class. That is, you cannot make an object of it. You can't write new SecondAbstractClass(). Ever. This is sensible, as it is the way the world works. The world has things in it, like balls and books and rocks. The world also has abstract concepts that help us organize actual things, such as rocks and people, and to organize other concepts. The economy is a good example. There is no such thing as “the economy.” Anywhere. It doesn't exist. We talk about it enough. “Blah blah blah…how's the economy…. Ah it's horrible…. Ah well what're you gunna do….” Because “the economy” is a useful placeholder for a collection of other things—some of which are physical objects, and some of which are ...

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