Copying a HashMap in Java
You can also use
clone()
Method to copy all elements from one hashmap to another hashmap
Program for copy all elements from one hashmap to another
import java.util.HashMap;public class CloneHashMap { public static void main(String a[]) { HashMap hashMap = new HashMap(); HashMap hashMap1 = new HashMap(); hashMap.put(1, "One"); hashMap.put(2, "Two"); hashMap.put(3, "Three"); System.out.println("Original HashMap : " + hashMap); hashMap1 = (HashMap) hashMap.clone(); System.out.println("Copied HashMap : " + hashMap1); } }
The difference is that in C++ your object is on the stack, whereas in Java, your object is in the heap. If A and B are Objects, any time in Java you do:
B = A
A and B point to the same object, so anything you do to A you do to B and vice versa.
Use new HashMap()
if you want two different objects.
And you can use Map.putAll(...)
to copy data between two Maps.