how to print the map in java

1import java.util.HashMap;
2import java.util.Iterator;
3import java.util.Map;
4import java.util.stream.Stream;
5 
6class MapUtil
7{
8    // Program to print all keys present in the Map using keySet() in Java
9    public static void main (String[] args)
10    {
11        Map<Integer, String> map = new HashMap<>();
12        map.put(1, "One");
13        map.put(2, "Two");
14 
15        // 1. using Iterator
16        Iterator<Integer> itr = map.keySet().iterator();
17        while (itr.hasNext()) {
18            System.out.println(itr.next());
19        }
20 
21        // 2. For-each Loop
22        for (Integer key : map.keySet()) {
23            System.out.println(key);
24        }
25 
26        // 3. Java 8 - Collection.iterator() + Iterator.forEachRemaining()
27        map.keySet().iterator()
28                .forEachRemaining(System.out::println);
29 
30        // 4. Java 8 - Collection.stream() + Stream.forEach()
31        map.keySet().stream()
32                .forEach(System.out::println);
33 
34        // Java 8 - Stream.of() + Collection.toArray() + Stream.forEach()
35        Stream.of(map.keySet().toArray())
36                .forEach(System.out::println);
37 
38        // 5. Convert to String
39        System.out.println(map.keySet().toString());
40 
41        // Java 8
42        Stream.of(map.keySet().toString())
43                .forEach(System.out::println);
44    }
45}
46

1// Java 8 - Collection.iterator() + Iterator.forEachRemaining()
2        map.keySet().iterator()
3                .forEachRemaining(System.out::println);