java-programming/javaUpdates/src/map/MapDemo.java at master · 9146887137/java-programming · GitHub

27 lines (20 loc) · 680 Bytes

package map;

import java.util.HashMap;

import java.util.concurrent.ConcurrentHashMap;

public class MapDemo {

public static void main(String[] args) {

ConcurrentHashMap<Integer, String> cm=new ConcurrentHashMap<Integer, String>();

cm.put(1,"akash");

cm.put(2,"ramesh");

cm.put(3,"abhi");

cm.put(4,"sumit");

System.out.println(cm);

System.out.println(ConcurrentHashMap.newKeySet());

HashMap<Integer, String> sm=new HashMap<Integer, String>(cm);

sm.put(null, null);

sm.put(7, null);

System.out.println(sm.computeIfAbsent(9, (a)->sm.get(a).concat("Akash")));

System.out.println(sm.keySet());

}

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