About Question com.enthuware.ets.scjp.v6.2.119 :

[Lodengruen]

The question asks for "hex numbers that are delimited by at least one whitespace at either end in an input text", so the "\b" in the solution expression is wrong in my opinion, since it allows the hex number to start with the first character or end with the last character, and I think "end of string" ist not a whitespace!

[admin]

It says, "whitespace at either end" not "at both ends", so I think it fine although I agree that it is not very clear.

HTH,
Paul.

[chang_surrey]

Although this question can be answered correctly through eliminating the wrong options, I think it's worth noting that "\b" is out of the exam's scope.

http://education.oracle.com/pls/web_pro ... id:1Z0-851

where Section 3 says the regex patterns will be limited to: . (dot), * (star), + (plus), ?, \d, \s, \w, [], ()

Thanks for the nice question though