Java for each loop working

Question

I was working on certain task, when incidentally did something wrong according to me but the code executed and provided correct result. I was little surpris

Answer 1

for-each loop of List will be internally converted to for loop with iterator.

  for (String output : mylist) 
      {
          System.out.println(output);
          mylist = new ArrayList(); //It worked 
          mylist.add(output);
      }

gets converted to

   for (Iterator iterator = mylist.iterator(); iterator.hasNext();) {
        String output = (String)iterator.next();
        System.out.println(output);
        mylist = new ArrayList(); //It worked 
        mylist.add(output); 
      }

And since the the snapshot of list is already taken at below

for (Iterator iterator = mylist.iterator(); iterator.hasNext();) {

The loop is running until the last element of list i.e. "how are you".

Whereas, below is not working because of FailFast behaviour of List.

for (String output : mylist) 
    {
        System.out.println(output);             
        mylist.add(output); // After this line it threw exception java.util.ConcurrentModificationException
    }

It says, if you are modifying the list while iterating, with anything other than iterator's own remove method, List will throw ConcurrentModificationException and thats the reason the below is working.

for (Iterator iterator2 = mylist.iterator(); iterator2.hasNext();)
{
    String string = (String) iterator2.next();
    System.out.println(string);
    iterator2.remove(); //It worked but if I used the same thing to remove element from original list it threw exception.
}