I believe this depends on each individual, there are people who read the JLS before they start coding. Others start coding straight away without looking to the language syntax until the need is there. Which one is better, it depends on how you feel best.
With regards to the exam I believe studying one objective at a time, and then taking mock exams in a simulated environment seems to be the most preferred way.
Once you get through all the objectives you can go for mock exams that contains a mixture of objectives.
Another possibility is taking a mock exam (trial exam), before you start studying, that covers all the objectives. The outcome of this mock exam will give a clear indication of your weaknesses and your strengths for each objective.
On our website we have created a personalized certification centre that you can use to
test first your strengths or test each objective individually.
As Marcus already indicated his questions seems to be close to the exam, from the feedback we receive we must believe that we fall in the same category.
The choice is yours ...