Iterator over HashMap in Java

Question

I tried to iterate over hashmap in Java, which should be a fairly easy thing to do. However, the following code gives me some problems:

HashMap hm = new HashMap(         


        

Answer 1

You should really use generics and the enhanced for loop for this:

Map hm = new HashMap<>();
hm.put(0, "zero");
hm.put(1, "one");

for (Integer key : hm.keySet()) {
    System.out.println(key);
    System.out.println(hm.get(key));
}

http://ideone.com/sx3F0K

Or the entrySet() version:

Map hm = new HashMap<>();
hm.put(0, "zero");
hm.put(1, "one");

for (Map.Entry e : hm.entrySet()) {
    System.out.println(e.getKey());
    System.out.println(e.getValue());
}