Some questions related to this exam if someone knows:
(A) Is still actually available , does anyone tried recently?
(B) What is the validity/expiration time?
(C) Any related materials to study, for e.g. enthuware does not have a related exam in their test engine?
Yes, they are still available. Oracle has not yet announced their retirement so they will be available for some time. However, I wouldn't recommend you take either. Neither serves as a pre-req to the OCP if you decide to continue. And they are for an old version of Java.
If you still want to take the exam, I recommend reading the SCJA study guide by Robert Liguori and Edward Finegan. (The exam was called the SCJA when it came out; it's the same thing as the OCJA). In fact the book is so old, that it looks like you can only buy it used and the publisher is no longer selling it.