1. package com.journaldev.util;
3. import java.util.HashMap;
4. import java.util.Iterator;
5. import java.util.Map;
6. import java.util.concurrent.ConcurrentHashMap;
8. public class ConcurrentHashMapExample {
10. public static void main(String[] args) {
12. //ConcurrentHashMap
13. Map<String,String> myMap = new ConcurrentHashMap<String,String>();
14. myMap.put("1", "1");
15. myMap.put("2", "1");
16. myMap.put("3", "1");
17. myMap.put("4", "1");
18. myMap.put("5", "1");
19. myMap.put("6", "1");
20. System.out.println("ConcurrentHashMap before iterator: "+myMap);
21. Iterator<String> it = myMap.keySet().iterator();
23. while(it.hasNext()){
24. String key = it.next();
25. if(key.equals("3")) myMap.put(key+"new", "new3");
26. }
27. System.out.println("ConcurrentHashMap after iterator: "+myMap);
29. //HashMap
30. myMap = new HashMap<String,String>();
31. myMap.put("1", "1");
32. myMap.put("2", "1");
33. myMap.put("3", "1");
34. myMap.put("4", "1");
35. myMap.put("5", "1");
36. myMap.put("6", "1");
37. System.out.println("HashMap before iterator: "+myMap);
38. Iterator<String> it1 = myMap.keySet().iterator();
40. while(it1.hasNext()){
41. String key = it1.next();
42. if(key.equals("3")) myMap.put(key+"new", "new3");
43. }
44. System.out.println("HashMap after iterator: "+myMap);
45. }
47. }

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