SCJP - 2 - Which declare a compilable abstract class? (Choose all that apply.)

2. Which declare a compilable abstract class? (Choose all that apply.)

A. public abstract class Canine { public Bark speak(); }
B. public abstract class Canine { public Bark speak() { } }
C. public class Canine { public abstract Bark speak(); }
D. public class Canine abstract { public abstract Bark speak(); }

Answer
:
B is correct. abstract classes don't have to have any abstract methods.

A is incorrect because abstract methods must be marked as such. C is incorrect because
you can't have an abstract method unless the class is abstract. D is incorrect because the
keyword abstract must come before the classname. (Objective 1.1)