Java Collection Tutorial - Java WeakHashMap.putAll(Map <? extends K ,? extends V > m)








Syntax

WeakHashMap.putAll(Map <? extends K ,? extends V > m) has the following syntax.

public void putAll(Map <? extends K ,? extends V > m) 

Example

In the following code shows how to use WeakHashMap.putAll(Map <? extends K ,? extends V > m) method.

//from  w  ww.  j a va 2 s .c  o m
import java.util.Map;
import java.util.WeakHashMap;

public class Main {
   public static void main(String[] args) { 
      Map<String, String>  weakHashMapOne = new WeakHashMap<String, String> ();
      Map<String, String>  weakHashMapTwo = new WeakHashMap<String, String> ();
            
      
      System.out.println("Populating two Maps");
    
      weakHashMapOne.put("1", "first");
      weakHashMapOne.put("2", "two");
      weakHashMapOne.put("3", "from java2s.com");
      
      weakHashMapTwo.put("1", "1st");
      weakHashMapTwo.put("2", "2nd");
      weakHashMapTwo.put("3", "3rd");
      
      // checking Map
      System.out.println("Before - Map 1: "+weakHashMapOne);
      System.out.println("Before - Map 2: "+weakHashMapTwo);
      
      // putting map 2 into map1
      weakHashMapOne.putAll(weakHashMapTwo);
      
      System.out.println("After - Map 1: "+weakHashMapOne);
      System.out.println("After - Map 2: "+weakHashMapTwo);
   }     
}

The code above generates the following result.