// Java program to iterate through the
// first map and put it in the second map

import java.util.HashMap;
import java.util.Map;

class GFG {
	public static <K, V> Map<K, V>
	copyMap(Map<K, V> original)
	{

		Map<K, V> second_Map = new HashMap<>();

		// Start the iteration and copy the Key and Value
		// for each Map to the other Map.
		for (Map.Entry<K, V> entry : original.entrySet()) {

			// using put method to copy one Map to Other
			second_Map.put(entry.getKey(),
						entry.getValue());
		}

		return second_Map;
	}

	public static void main(String[] args)
	{

		Map<String, Integer> hashMap = new HashMap<>();
		hashMap.put("A", 1);
		hashMap.put("B", 2);
		hashMap.put("C", 3);
		
		// copyMap method would copy the original
		// hashMap to second_Map
		Map<String, Integer> second_Map = copyMap(hashMap);
		
		System.out.println(second_Map);
	}
}

Output

{A=1, B=2, C=3}

Method 2: Using putAll(k, v) Method.

Map.putAll(k,v) method is used to copy one HashMap to another empty HashMap.

Syntax:

new_hash_map.putAll(exist_hash_map)

Parameters: 

// Java program to copy hashmap to
// another hashmap using putAll() method

import java.util.HashMap;
import java.util.Map;

class GFG {
	public static <K, V> Map<K, V>
	copyMap(Map<K, V> original)
	{

		Map<K, V> second_map = new HashMap<>();

		// using putAll method to copy from original Map to
		// second_map
		second_map.putAll(original);

		return second_map;
	}

	public static void main(String[] args)
	{

		Map<String, Integer> hashMap = new HashMap<>();

		hashMap.put("A", 1);
		hashMap.put("B", 2);
		hashMap.put("C", 3);

		// copyMap method would copy the original
		// hashMap to second_Map
		Map<String, Integer> second_map = copyMap(hashMap);
		
		System.out.println(second_map);
	}
}

Output

{A=1, B=2, C=3}

Method 3: Using copy constructor.

It is one among the shortest and easiest ways to repeat one HashMap to a different .

We can use a replica constructor to repeat a map which may be a special constructor for creating a replacement object as a replica of an existing object.

import java.util.HashMap;
import java.util.Map;

class GFG {
	
	// usimg copy constructor to resturn the original map
	// and then copy it in second_map
	public static <K, V> Map<K, V> copyMap(Map<K, V> original)
	{
	// constructor by passing original hashmap
	// in the parameter returns the new hashmap
	// with the copied content of the original one
		return new HashMap<>(original);
	}

	public static void main(String[] args)
	{

		Map<String, Integer> hashMap = new HashMap<>();

		hashMap.put("A", 1);
		hashMap.put("B", 2);
		hashMap.put("C", 3);
		
		// copyMap method would copy the original
		// hashMap to second_Map
		Map<String, Integer> second_map = copyMap(hashMap);

		System.out.println(second_map);
	}
}

Output

{A=1, B=2, C=3}