About Question enthuware.ocpjp.v7.2.1527 :

[Wisevolk]

Hi,
First I think there is an error in the question's syntax :

"Which of the following classes can be made abstract just be adding the keyword abstract in their declaration?"
Should be "by" no ?

Second :
The question should be which of the following valid classes can be made....

Because except the fourth answer, the others with abstract added are all good !!

[admin]

1. Yes. Fixed. Thank you for your feedback!
2. No, you can't make classes in option 2, 3, and 4 abstract just by added the abstract keyword to their declaration as explained in their explanations. Whether they are valid currently is immaterial.

HTH,
Paul.

[Wisevolk]

You're right I was thinking to add abstract everywhere it was needed !! but the question says for class declaration.