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Thread: return type of iterator() method

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    Angry return type of iterator() method

    what does the iterator() method return???it can't return an object of Iterator as it's an interface...


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    Default Re: return type of iterator() method

    Welcome to the forum! Please read this topic to learn how to post code correctly and other useful info for new members.

    Refer to the API for the answer to your question.

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    Default Re: return type of iterator() method

    Quote Originally Posted by msnishan View Post
    what does the iterator() method return???it can't return an object of Iterator as it's an interface...
    Exactly! Iterator is an interface. All standard collections in the framework (and in general any type that implements Iterable) return an implementation of Iterator. Typically this implementation is realized with an internal class (typically an "inner class", regular or anonymous) that is generally not visible outside the class of the collection.

    So an iterator() method is typically constructed in a similar way like this:

    public Iterator<E> iterator() {
        return new InternalIteratorImpl();
    }
    or with anonymous inner class:
    public Iterator<E> iterator() {
        return new Iterator() {
            //......implementation of hasNext/next/remove methods .....
        };
    }
    Andrea, www.andbin.net SCJP 5 (91%) SCWCD 5 (94%)

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