I thnk for the purpose of the exam you only need to kno when to use them
i.e which collection would most satisfy a particular set of conditions..ie which wud provide unique elements ,key value pairs etc..these it self an be tricky at times but are mostly easy.
In majority of the mock tests that is what is covered but the khalid mughal
gives a lot more information..If you have the time do go thru it.
Also give the
test at javacertificate.com there are a lot of questions on collection implemention there if you want to get scared and start studying the chapter all over again..
But I thnk
you should wait for a reply from someone Higher up the Ladder.