Does JVM keeps track of index in foreach loop in Java? If so, How?

Question

I know it's not possible to get the index in foreach loop. Either we need to use normal loop or use an index which gets incremented/decremented in each iteration.

I have followed this question also. Java, How do I get current index/key in “for each” loop.

I just want to know whether, Java keeps any index in each iteration. If so, how?

Answer 1

Depends.

There are two versions of this loop, for arrays and for Iterable (things like List).

For arrays, the compiler will create a "normal" for (int i=0; i<arr.length; i++) loop. So here you have that index.

For Iterable, it becomes while(iter.hasMore()){. So there is no index in the loop itself. Depending on the Iterable implementation, there may still be one inside the Iterator.