To Remove Duplicate keys From Map in Java we are approaches following scenarios. ConcurrentHashMap is used to store data in key-value pairs.
- When duplicate keys are used, then previous key will be overwritten from current key.
- First we create a ConcurrentHashMap object and pass key-value data to them.
- From keySet() method we find the key and store in Set s.
- Now we iterate the map and store key and value in one declare parameter.
- While iterating we get the data object from key.
- Inside if condition we compare both value and data object.
- If condition return true then pass key inside remove method to removing duplicate key.
- Now print the map.
import java.util.Iterator;
import java.util.Set;
import java.util.concurrent.ConcurrentHashMap;
public class RemoveDuplcateMapKey {
public static void main(String[] args) {
ConcurrentHashMap<String, Integer> map = new ConcurrentHashMap<String, Integer>();
map.put("java", 8);
map.put("Spring", 6);
map.put("hibernate", 1);
map.put("java", 9);
Set s = map.keySet();
Iterator itr = s.iterator();
Object key, value;
System.out.println("After remove duplicate key :-");
while (itr.hasNext()) {
key = itr.next();
value = map.get(key);
Object data = map.get(key);
if (value == data) {
map.remove(key);
}
System.out.println(key + " ------- " + data);
}
}
}
Output :-
After remove duplicate key :-
java ——- 9
Spring ——- 6
hibernate ——- 1