dictionary - How do I efficiently iterate over each entry in a Java Map?

The ordering will always depend on the specific map implementation.
Using Java 8 you can use either of these:

map.forEach((k,v) -> { System.out.println(k + ":" + v); });

Or:

map.entrySet().forEach((e) -> {
            System.out.println(e.getKey() + " : " + e.getValue());
        });

The result will be the same (same order). The entrySet backed by the map so you are getting the same order. The second one is handy as it allows you to use lambdas, e.g. if you want only to print only Integer objects that are greater than 5:

map.entrySet()
    .stream()
    .filter(e-> e.getValue() > 5)
    .forEach(System.out::println);

The code below shows iteration through LinkedHashMap and normal HashMap (example). You will see difference in the order:

public class HMIteration {


    public static void main(String[] args) {
        Map linkedHashMap = new LinkedHashMap<>();
        Map hashMap = new HashMap<>();

        for (int i=10; i>=0; i--) {
            linkedHashMap.put(i, i);
            hashMap.put(i, i);

        }

        System.out.println("LinkedHashMap (1): ");
        linkedHashMap.forEach((k,v) -> { System.out.print(k + " (#="+k.hashCode() + "):" + v + ", "); });

        System.out.println("\nLinkedHashMap (2): ");

        linkedHashMap.entrySet().forEach((e) -> {
            System.out.print(e.getKey() + " : " + e.getValue() + ", ");
        });



        System.out.println("\n\nHashMap (1): ");
        hashMap.forEach((k,v) -> { System.out.print(k + " (#:"+k.hashCode() + "):" + v + ", "); });

        System.out.println("\nHashMap (2): ");

        hashMap.entrySet().forEach((e) -> {
            System.out.print(e.getKey() + " : " + e.getValue() + ", ");
        });

    }
}

LinkedHashMap (1):

10 (#=10):10, 9 (#=9):9, 8 (#=8):8, 7 (#=7):7, 6 (#=6):6, 5 (#=5):5, 4 (#=4):4, 3 (#=3):3, 2 (#=2):2, 1 (#=1):1, 0 (#=0):0,

LinkedHashMap (2):

10 : 10, 9 : 9, 8 : 8, 7 : 7, 6 : 6, 5 : 5, 4 : 4, 3 : 3, 2 : 2, 1 : 1, 0 : 0,

HashMap (1):

0 (#:0):0, 1 (#:1):1, 2 (#:2):2, 3 (#:3):3, 4 (#:4):4, 5 (#:5):5, 6 (#:6):6, 7 (#:7):7, 8 (#:8):8, 9 (#:9):9, 10 (#:10):10,

HashMap (2):

0 : 0, 1 : 1, 2 : 2, 3 : 3, 4 : 4, 5 : 5, 6 : 6, 7 : 7, 8 : 8, 9 : 9, 10 : 10,