If you declare a class "abstract" then it cannot be instantiated. That is you can't make an instance of it.
The diffrence between an abstract class and a interface is that an abstract class can have none abstract methods.
If
you should make a abstract class of a man,woman,boy,etc then you should try to locate something that they all have incommon.
Ears, Eyes, head, neck, body, and so on.
In an abstract class you can return values in a method
if you had a abstract method in the abstract class then you would force the Girl class to include the method.
Here you would have a compile error because the Girl class didn't include the getName method. It's up to the Girl class to supply the implementation of the getName() method.
Hope this make sence. There are probably experienced java programmers that would explain this more clearly.
// Mathias