HashMapDemo.java

packagesection16_Hashmap;

importjava.util.Collection;
importjava.util.HashMap;
importjava.util.Map;
importjava.util.Set;

publicclassHashMapDemo {

publicstaticvoidmain(String[] args) {

HashMap<String, Integer> map = newHashMap<String, Integer>();

map.put("USA", 1000);
map.put("Nepal", 50);
map.put("India", 200);
map.put("Germany", 500);

System.out.println(map);

System.out.println(map.get("USA"));
System.out.println(map.get("Canada"));

System.out.println(map.containsKey("USA"));
System.out.println(map.containsKey("China"));

System.out.println(map.remove("India"));
System.out.println(map);

System.out.println("\n------keys---------");
Set<String> keys = map.keySet();

for (Stringkey : keys) {
System.out.println(key);
 }

System.out.println("\n------values---------");
Collection<Integer> values = map.values();

for (Integerval : values) {
System.out.println(val);
 }

System.out.println("\n------key, values - entrySet---------");
Set<Map.Entry<String, Integer>> entries = map.entrySet();

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

}