Concurrent Modification exception

Question

I have this little piece of code and it gives me the concurrent modification exception. I cannot understand why I keep getting it, even though I do not see any concurrent mo

Answer 1

I cannot understand why I keep getting it, even though I do not see any concurrent modifications being carried out.

Between creating the iterator and starting to use the iterator, you added arguments to the list that is to be iterated. This is a concurrent modification.

    ListIterator it = s.listIterator();  

    for (String a : args)
        s.add(a);                    // concurrent modification here

    if (it.hasNext())
        String item = it.next();     // exception thrown here

Create the iterator AFTER you've finished adding elements to the list:

    for (String a : args)
        s.add(a); 

    ListIterator it = s.listIterator();  
    if (it.hasNext())
        String item = it.next();