title: UnsupportedOperationException when trying to remove a list of items from another list
body: <p>I have coded below, i dint know what is wrong but validDatesIterator.remove() is giving me UnsupportedOperationException exception. Using java 1.6</p>
  
  <pre><code>List&lt;Integer&gt; validDates = Arrays.asList(26,27,28,1,2,3,4);
      List&lt;Integer&gt; daysToBeRemoved = Arrays.asList(1,2); 
      Iterator&lt;Integer&gt; validDatesIterator = validDates.listIterator();
      while(validDatesIterator.hasNext()) {
          Integer curValue = validDatesIterator.next();
          for(Integer dayToRemove:daysToBeRemoved) {
              if(curValue.equals(dayToRemove)) {
                  validDatesIterator.remove();
                  break;
              }
          }
      }
  </code></pre>
  
  <p>Also When i debug valid dates(curValue initially it gives 27, instead 26) is starting with element 27, not 26.</p>
  
  <p>May be a duplicate question, but searched a lot, dint find kinda of this. Please help.</p>