how to print the map in java
import java.util.HashMap; import java.util.Iterator; import java.util.Map; import java.util.stream.Stream; class MapUtil { // Program to print all keys present in the Map using keySet() in Java public static void main (String[] args) { Map<Integer, String> map = new HashMap<>(); map.put(1, "One"); map.put(2, "Two"); // 1. using Iterator Iterator<Integer> itr = map.keySet().iterator(); while (itr.hasNext()) { System.out.println(itr.next()); } // 2. For-each Loop for (Integer key : map.keySet()) { System.out.println(key); } // 3. Java 8 - Collection.iterator() + Iterator.forEachRemaining() map.keySet().iterator() .forEachRemaining(System.out::println); // 4. Java 8 - Collection.stream() + Stream.forEach() map.keySet().stream() .forEach(System.out::println); // Java 8 - Stream.of() + Collection.toArray() + Stream.forEach() Stream.of(map.keySet().toArray()) .forEach(System.out::println); // 5. Convert to String System.out.println(map.keySet().toString()); // Java 8 Stream.of(map.keySet().toString()) .forEach(System.out::println); } }
