Which three are valid method signatures in an interface?
1.private int getArea();
2.public float getVol(float x);
3.public void main(String [] args);
4.public static void main(String [] args);
5.boolean setFlag(Boolean [] test);
Answer: B
(2), (3), and (5). These are all valid interface method signatures.
(1), is incorrect because an interface method must be public; if it is not explicitly declared public it will be made public implicitly. (4) is incorrect because interface methods cannot be static.