HashMap clone() Method in Java
Last Updated :
01 Nov, 2021
Let us do clear out the foundation concept of shallow copy and deep copy in java. Shallow repetition is quicker. However, it’s “lazy” it handles pointers and references. Rather than creating a contemporary copy of the particular knowledge the pointer points to, it simply copies over the pointer price. So, each the first and therefore the copy can have pointers that reference constant underlying knowledge. On another side, deep copy or deep repetition truly clones the underlying data. It is not shared between the first and therefore the copy.
The java.util.HashMap.clone() method is present inside java.util package which typically 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.
Example 1:
Java
import java.util.*;
public class GFG {
public static void main(String[] args)
{
HashMap<Integer, String> hash_map
= new HashMap<Integer, String>();
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" );
System.out.println( "Initial Mappings are: "
+ hash_map);
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}
Example 2:
Java
import java.util.*;
public class GFG {
public static void main(String[] args)
{
HashMap<String, Integer> hash_map
= new HashMap<String, Integer>();
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 );
System.out.println( "Initial Mappings are: "
+ hash_map);
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.
- clone() method does the shallow copy. But here the values in the original and cloned hashmap will not affect each other because primitive data type is used.
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