If I have a hash map and iterate over the objects repeatedly, is it correct that I'm not guaranteed the same order for every call? For example, could the following print two lines that differ from each other:

Map<String,Integer> map = new HashMap<String,Integer>()
  {{ put("a", 1); put("b", 2); put("c", 3); }};
System.out.println(map);
System.out.println(map);

And is this the case for sets and collections in general? If so, what's the best way in case you have to iterate twice over the same collection in the same order (regardless of what order that is)? I guess converting to a list.