[java] Java foreach loop: for (Integer i : list) { ... }

When I use JDK5 like below

ArrayList<Integer> list = new ArrayList<Integer>();  
     for (Integer i : list) { 

      //cannot check if already reached last item

   }

on the other hand if I just use an Iterator

ArrayList<Integer> list = new ArrayList<Integer>();
  for (Iterator i = list.iterator(); i.hasNext();) {

          //i can check whether this is last item
          if(i.hasNextItem()){
          }

    }

How can I check if I've already reached last item with for (Integer i : list) {

The API does not support that directly. You can use the for(int i..) loop and count the elements or use subLists(0, size - 1) and handle the last element explicitly:

  if(x.isEmpty()) return;
  int last = x.size() - 1;
  for(Integer i : x.subList(0, last)) out.println(i);
  out.println("last " + x.get(last));

This is only useful if it does not introduce redundancy. It performs better than the counting version (after the subList overhead is amortized). (Just in case you cared after the boxing anyway).

Sometimes it's just better to use an iterator.

(Allegedly, "85%" of the requests for an index in the posh for loop is for implementing a String join method (which you can easily do without).)

Another way, you can use a pass-through object to capture the last value and then do something with it:

List<Integer> list = new ArrayList<Integer>();
Integer lastValue = null;
for (Integer i : list) {
    // do stuff
    lastValue = i;
}
// do stuff with last value