The @Override annotation exists to help you catch mistakes like writing hashcode() instead of hashCode(). If you would have used it, like this:
then you would have gotten a compiler error, telling you that hashcode() does not override any method in a superclass.
By adding @Override to a method, you tell the compiler that the method is supposed to override a superclass method - and if it doesn't, the compiler will complain.
Annotations are not part of the
SCJP exam, but it's useful to know them ofcourse.