About Question com.enthuware.ets.scjp.v6.2.314 :

[Deepa]

Does String class have hashCode() as a method?

[admin]

Every class has this method because it is present in Object class from which every class directly or indirectly extends.

[leisenstein]

It really seems like Oracle just wants people to memorize EVERY SINGLE method in the String and StringBuffer class. Then, try to trip them up by mixing/matching them in questions.

I realize you should have a good understanding of each, but memorizing the methods seems useless.