The throw keyword is used to actually throw an exception while the throws keyword just tells the compiler which exceptions may be thrown by a method.

Code: Select all

public Object pop() throws EmptyStackException
{
    Object obj;

    if (size == 0) {
        throw new EmptyStackException();
    }

    obj = objectAt(size - 1);
    setObjectAt(size - 1, null);
    size--;
    return obj;
}

See haw throws appears in the declaration of the method and throw appears in its body.