ADDITIONAL SYSTEM INFORMATION :
JDK SE 1.8

A DESCRIPTION OF THE PROBLEM :
I created an iterator() and then removed the 1st entry form the map before iterating it, I always get 1st item present in the iterator, But when I remove 2nd or proceeding entries, the current iterator removes that entry.

Example of removing 1st entry form map:

    Map<Integer,Integer> m1 = new ConcurrentHashMap();
    m1.put(4, 1);
    m1.put(5, 2);
    m1.put(6, 3);
    Iterator i1 = m1.entrySet().iterator();
    m1.remove(4); // remove entry from map
    while (i1.hasNext())
        System.out.println("value :: "+i1.next()); //still shows entry 4=1
and the output is:

value :: 4=1
 value :: 5=2
 value :: 6=3

Example of removing 3rd entry form map:

    Map<Integer,Integer> m1 = new ConcurrentHashMap();
    m1.put(4, 1);
    m1.put(5, 2);
    m1.put(6, 3);
    Iterator i1 = m1.entrySet().iterator();
    m1.remove(6); // remove entry from map
    while (i1.hasNext())
        System.out.println("value :: "+i1.next()); //does not shows entry 6=3
and the output is:

value :: 4=1
 value :: 5=2

Why removing 1st entry from map does not reflect but removing 2nd or proceeding entries reflect in iterator()?

While https://docs.oracle.com/javase/8/docs/api/java/util/concurrent/ConcurrentHashMap.html says:

Iterators, Spliterators and Enumerations return elements reflecting the state of the hash table at some point at or since the creation of the iterator/enumeration. They do not throw ConcurrentModificationException.

That means, its iterators reflect the state of the hash table at point of the creation of the iterator. And when we remove/add an entry from the Map, the Iterator will show the originally obtained entries from map?


FREQUENCY : always