Java Coding Interview programming Questions : Java Test on HashMap

1.What will be the Output of this program.

1. public class HashMapJavaTricky{
2.  
3. public static void main(String[] args) {
4.  
5.     HashMap<Integer,String> hm= new HashMap<Integer, String>();  
6. 
   
7.      hm.put(1, "one");
8.      hm.put(2, "two");
9.      hm.put(3, "three");
10.  
11.     System.out.println(hm.size()); 
12.  
13. for (Integer name: hm.keySet()){
14.  
15.    System.out.println(name + " " + hm.get(name)); 
16.   
17. }
18.  
19. }
20. }

1. 3
2. 1 one
3. 2 two
4. 3 three

2.Basics of java programming : Hashmap

1. public class HashMapJavaTricky{
2.  
3. public static void main(String[] args) {
4.  
5.     HashMap<Integer,String> hm= new HashMap<Integer, String>();  
6. 
   
7.      hm.put(1, "one");
8.      hm.put(2, "two");
9.      hm.put(3, "three");
10.  
11.      hm.put(1, "ONE");
12.  
13.     System.out.println(hm.size()); 
14.  
15. for (Integer name: hm.keySet()){
16.  
17.    System.out.println(name + " " + hm.get(name)); 
18.   
19. }
20.  
21. }
22. }

1. 3
2. 1 ONE
3. 2 two
4. 3 three

3.Java programming examples: Hashmap

1. public class HashMapJavaTricky{
2.  
3. public static void main(String[] args) {
4.  
5.     HashMap<Integer,String> hm= new HashMap<Integer, String>();  
6. 
   
7.      hm.put(1, "one");
8.      hm.put(2, "two");
9.      hm.put(3, "three");
10.  
11.      hm.put(1, "ONE");
12.      hm.put(null,null);
13.  
14.     System.out.println(hm.size()); 
15.  
16. for (Integer name: hm.keySet()){
17.  
18.    System.out.println(name + " " + hm.get(name)); 
19.   
20. }
21.  
22. }
23. }

1. 4
2. null null
3. 1 ONE
4. 2 two
5. 3 three

4.Java programming for beginners : HashMap

1. public class HashMapJavaTricky{
2.  
3. public static void main(String[] args) {
4.  
5.     HashMap<Integer,String> hm= new HashMap<Integer, String>();  
6. 
   
7.      hm.put(1, "one");
8.      hm.put(2, "two");
9.      hm.put(3, "three");
10.  
11.      hm.put(1, "ONE");
12.      hm.put(null,null);
13.  
14.      Integer i=null;
15.      String str="java programming basics Interview questions";
16.  
17.      hm.put(i, str);
18.  
19.     System.out.println(hm.size()); 
20.  
21. for (Integer name: hm.keySet()){
22.  
23.    System.out.println(name + " " + hm.get(name)); 
24.   
25. }
26.  
27. }
28. }

1. 4
2. null java programming basics Interview questions
3. 1 ONE
4. 2 two
5. 3 three