File APIs for Java Developers
Manipulate DOC, XLS, PPT, PDF and many others from your application.
The moose likes Programmer Certification (SCJP/OCPJP) and the fly likes JQ+ question on interfaces Big Moose Saloon
  Search | Java FAQ | Recent Topics | Flagged Topics | Hot Topics | Zero Replies
Register / Login
JavaRanch » Java Forums » Certification » Programmer Certification (SCJP/OCPJP)
Bookmark "JQ+ question on interfaces" Watch "JQ+ question on interfaces" New topic

JQ+ question on interfaces

natarajan meghanathan
Ranch Hand

Joined: Feb 01, 2001
Posts: 130
Which of the following with interfaces are true: [check 2 answers]
1) Interfaces are abstract by default.
2) An Interface can have static methods.
3) Interfaces cannot be final.
4) Fields of an interface can be declared transient, volatile but not synchronized.
5) All methods in an interface are abstract, although u need not declare them to be so.
I went for 1,3
But the answer given is 1,5.
There is a mild catch i thought which made me to go for 3 rather than 5. They say u need not declare the methods as abstract in option 5. That means i thought, it is legal to declare them to be abstract (which is not so!!). So i went for option 3 which is also perfectly true. (Interfaces cannot be declared final!!).
Any help.

Sun Certified Programmer for Java 2 Platform
Paul Anilprem
Enthuware Software Support
Ranch Hand

Joined: Sep 23, 2000
Posts: 3411
Your are right. Interfaces cannot be final. This was a bug in the question. I remember fixing it a couple days ago.
But it is legal to declare a method as abstract in an interface. It is not recommended to do so, though.
Get Certified, Guaranteed!
(Now Revised for the new Pattern)

Enthuware - Best Mock Exams and Questions for Oracle/Sun Java Certifications
Quality Guaranteed - Pass or Full Refund!
I agree. Here's the link:
subject: JQ+ question on interfaces