- Is is pronounced every bit HashMap because It is hash tabular array based implementation of map interface.
- It extends AbstractMap shape together with implements Map interface.
- It allows to shop null fundamental together with null values.
- It is non synchronized implementation hence if multiple threads accessing it concurrently together with whatever i of them modifies it together with then it must live on synchronized externally.
- It does non guarantee of maintaining the map order.
- void clear() : It volition take away together with clear all mapping entries from map.
- Object clone() : It volition supply you lot shallow re-create of this map.
- boolean containsKey(Object key) : It volition depository fiscal establishment tally together with render truthful if specified fundamental has whatever mapping inwards this map.
- boolean containsValue(Object value) : It volition depository fiscal establishment tally together with render truthful if whatever fundamental has mapping alongside given value.
- Set<Map.Entry<K,V>> entrySet() : It volition render the gear upwards thought of mapping.
- V get(Object key) : teach method is used for retrieving value of specified fundamental from this map. If no mapping found, It volition render null.
- boolean isEmpty() : It volition depository fiscal establishment tally together with render truthful if map is empty.
- Set<K> keySet() : It volition render gear upwards thought of the keys of this map.
- V put(K key, V value) : It volition associate specified fundamental value mapping inwards this map.
- void putAll(Map<? extends K,? extends V> m) : It volition re-create all key-value mapping yoke of specified map to this map.
- V remove(Object key) : It volition take away mapping of specified fundamental from this map.
- int size() :It volition render size of this map.
- Collection<V> values() : It volition render collection thought of map values.
HashMapExample :
package JAVAExamples; import java.util.HashMap; import java.util.Iterator; import java.util.Map; world shape HashMapExample { world static void main(String[] args) { // practise Map Map<Integer, String> k = novel HashMap<Integer, String>(); // Add fundamental alongside value inwards map. m.put(3,"Chicago"); m.put(7,"Mumbai"); m.put(1,"Tokyo"); m.put(5,"Delhi"); m.put(2,"Paris"); m.put(8,"Beijing"); m.put(11,"Berlin"); //Print map System.out.println("Map : "+m); // Get size of map. System.out.println("Map size is : " + m.size()); //Check if map is empty. System.out.println("Map is empty? : "+m.isEmpty()); //Remove mapping from map. m.remove(3); System.out.println("Map value later removing mapping of fundamental three : "+m); //Get value from map for specified key. System.out.println("Value for fundamental v is : "+m.get(5)); //Iterating over map. Iterator<Integer> keySetIterator = m.keySet().iterator(); while(keySetIterator.hasNext()){ Integer fundamental = keySetIterator.next(); System.out.println("key: " + fundamental + " value: " + m.get(key)); } //Check if map contains specified key. System.out.println("Map has fundamental vii ? : "+m.containsKey(7)); //Check if map contains specified value. System.out.println("Map has value xx ? : "+m.containsValue("Ahmedabad")); } }Output :
Map : {1=Tokyo, 2=Paris, 3=Chicago, 5=Delhi, 7=Mumbai, 8=Beijing, 11=Berlin} Map size is : vii Map is empty? : fake Map value later removing mapping of fundamental three : {1=Tokyo, 2=Paris, 5=Delhi, 7=Mumbai, 8=Beijing, 11=Berlin} Value for fundamental v is : Delhi key: 1 value: Tokyo key: ii value: Paris key: v value: Delhi key: vii value: Bombay key: 8 value: Beijing key: eleven value: Berlin Map has fundamental vii ? : truthful Map has value xx ? : false