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HashMap clone() Method in Java
  • Difficulty Level : Basic
  • Last Updated : 26 Nov, 2018

The java.util.HashMap.clone() method is used to return a shallow copy of the mentioned hash map. It just creates a copy of the map.

Syntax:

Hash_Map.clone()

Parameters: The method does not take any parameters.

Return Value: The method just returns a copy of the HashMap.

Below programs are used to illustrate the working of java.util.HashMap.clone() Method:
Program 1: Mapping String Values to Integer Keys.






// Java code to illustrate the clone() method
import java.util.*;
  
public class Hash_Map_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty HashMap
        HashMap<Integer, String> hash_map = new HashMap<Integer, String>();
  
        // Mapping string values to int keys
        hash_map.put(10, "Geeks");
        hash_map.put(15, "4");
        hash_map.put(20, "Geeks");
        hash_map.put(25, "Welcomes");
        hash_map.put(30, "You");
  
        // Displaying the HashMap
        System.out.println("Initial Mappings are: " + hash_map);
  
        // Displaying the cloned HashMap using clone()
        System.out.println("The cloned map look like this: " + hash_map.clone());
    }
}


Output:

Initial Mappings are: {20=Geeks, 25=Welcomes, 10=Geeks, 30=You, 15=4}
The cloned map look like this: {25=Welcomes, 10=Geeks, 20=Geeks, 30=You, 15=4}

Program 2: Mapping Integer Values to String Keys.




// Java code to illustrate the clone() method
import java.util.*;
  
public class Hash_Map_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty HashMap
        HashMap<String, Integer> hash_map = new HashMap<String, Integer>();
  
        // Mapping int values to string keys
        hash_map.put("Geeks", 10);
        hash_map.put("4", 15);
        hash_map.put("Geeks", 20);
        hash_map.put("Welcomes", 25);
        hash_map.put("You", 30);
  
        // Displaying the HashMap
        System.out.println("Initial Mappings are: " + hash_map);
  
        // Displaying the cloned HashMap using clone()
        System.out.println("The cloned map look like this: " + hash_map.clone());
    }
}


Output:

Initial Mappings are: {4=15, Geeks=20, You=30, Welcomes=25}
The cloned map look like this: {Geeks=20, 4=15, You=30, Welcomes=25}

Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.

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