Why make private inner class member public in Java?

Question

What is the reason of declaring a member of a private inner class public in Java if it still can\'t be accessed outside of containing class? Or can it?

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Answer 1

It is useful when you implement any interface.

class DataStructure implements Iterable {

    @Override
    public Iterator iterator() {
        return new InnerEvenIterator();
    }
    // ...        

    private class InnerEvenIterator implements Iterator {
        // ...    
        public boolean hasNext() { // Why public?
            // ...
            return false;
        }

        @Override
        public DataStructure next() {
            throw new UnsupportedOperationException("Not supported yet.");
        }

        @Override
        public void remove() {
            throw new UnsupportedOperationException("Not supported yet.");
        }
    }

    public static void main(String[] ex) {
        DataStructure ds = new DataStructure();
        Iterator ids = ds.iterator();
        ids.hasNext(); // accessable            
    }
}