This week's book giveaway is in the OCAJP 8 forum. We're giving away four copies of OCA Java SE 8 Programmer I Study Guide and have Edward Finegan & Robert Liguori on-line! See this thread for details.
This is written under the two-minute drill of the first chapter on SCJP 6 Sun Certified Java Programmer Study Guide by Kathy Sierra and Bert Bates:
A legal nonabstract implementing class has the following properties:
It provides concrete implementations for the interface's methods. (1)
It must follow all legal override rules for the methods it implements. (2)
It must not declare any new checked exceptions for an implementation method. (3)
It must not declare any checked exceptions that are broader than the exceptions declared in the interface method. (4)
It may declare runtime exceptions on any interface method implementation regardless of the interface declaration. (5)
It must maintain the exact signature (allowing for covariant returns) and return type of the methods it implements (but does not have to declare the exceptions of the interface). (6)
I've finished reading the Chapter 1, and after reading this two-minute drill, I'm positive that those that (3-6) are not discussed on Chapter 1 (I'm positive there's a chapter dedicated to this but not this chapter). Anyway, I just want to understand those things now so I thought I ask here. I would appreciate it if anyone can expound on item (2-6) (with/without examples would do). Thanks!