The real exam database has hundreds of questions in it. It is really difficult to memorise the actual questions. Arguably it is probably easier to learn Java. Do some people cheat, yes, are they successful? sometimes. Do people use "dumps"? yes. Are the dumps actually accurate, sometimes.
Frequently they are reconstructed from memory by people who have taken the exam and are laughably innaccurate due to the fragility of memory and the pressure of the exam situation. Should Sun change the question bank more frequently? probably. Do employers generally assume that someone with the SCJP has passed through cheating, No. Does any sensible employer check a candidates understanding further. Yes. Move along nothing to see, film at 11.