Java program to remove key value from hashmap

hashmap java Collections interview Questions

1.Basic java example program to remove value from hashmap.

• using  Object remove(Object key) method we can remove key value pair of hashmap.

1. package com.javaremovevaluehashmap;
2.  
3. import java.util.Hashmap;
4. import java.util.Iterator;
5. import java.util.Map;
6. import java.util.Map.Entry;
7.  
8. public class HashmapExample{
9.  
10. public static void main(String[] args) {
11.   
12. //create an Hashmap object
13. HashMap<String, String> hashmap = new HashMap();
14.        
15. //Add key values pairs to hashmap
16.         
17. hashmap.put("1","One");
18. hashmap.put("2","Two");
19. hashmap.put("3","Three");
20. hashmap.put("4","Four");
21. hashmap.put("5","Five");
22. hashmap.put("6","Six");       
23.       String key=null;
24.       String value="java programming basics Interview questions";   
25. hashmap.put(key,value);
26.  
27. /*
28. To remove a key value pair from HashMap use
29. Object remove(Object key) method of HashMap class.
30. It returns either the value mapped with the key or null if no value
31. was mapped.    
32.  */      
33.  
34.  Object object = hashmap.remove("4");
35.         System.out.println(object + " Removed from HashMap");
36.     
37.  
38. if(!hashmap.isEmpty()){
39.  
40. Iterator it=hashmap.entrySet().iterator();
41.              
42. while(it.hasNext()){
43. 
    
44. Map.Entry obj=(Entry) it.next();
45. System.out.print(obj.getKey()+" ");
46. System.out.println(obj.getValue());
47.              
48. }           
49. }   
50.  
51. }
52.  
53. }
     

Output:

1. Four Removed from HashMap
2. null java programming basics Interview questions
3. 1 One
4. 2 Two
5. 3 Three
6. 5 Five
7. 6 Six

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Java program to remove key value from hashmap

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