How to iterate in a HashMap in Java

Question

I have a HashMap and I want to iterate the Map.

How to do that?

Answer 1

You can use for but in a different way

for (Map.Entry<Integer, Integer> entry : HashMapName.entrySet())
{
    System.out.println(entry.getKey()+" = "+entry.getValue());
}

This way you can iterate over HashMap and get the different values accordingly.

Hope this helps.

Answer 2

Iterating using Iterator.

Using Generics:

Map<Integer, Integer> map = new HashMap<Integer, Integer>();
Iterator<Map.Entry<Integer, Integer>> entries = map.entrySet().iterator();
while (entries.hasNext()) {
    Map.Entry<Integer, Integer> entry = entries.next();
    System.out.println("Key = " + entry.getKey() + ", Value = " + entry.getValue());
}

Without Generics:

Map map = new HashMap();
Iterator entries = map.entrySet().iterator();
while (entries.hasNext()) {
    Map.Entry entry = (Map.Entry) entries.next();
    Integer key = (Integer)entry.getKey();
    Integer value = (Integer)entry.getValue();
    System.out.println("Key = " + key + ", Value = " + value);
}