java.util.WeakHashMap.entrySet() Method



The entrySet() method is used to return a collection view of the mappings contained in this map. Each element in the returned collection is a Map.Entry. The collection is backed by the map, so changes to the map are reflected in the collection and reverse.


Following is the declaration for java.util.WeakHashMap.entrySet() method.

public Set<Map.Entry<K,V>> entrySet()


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Return Value

The method call returns a collection view of the mappings contained in this map.


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The following example shows the usage of java.util.WeakHashMap.entrySet() method.

package com.tutorialspoint;

import java.util.Map;
import java.util.Set;
import java.util.WeakHashMap;

public class WeakHashMapDemo {
   public static void main(String[] args) { 
   Map<String, String> weakHashMap = new WeakHashMap<String, String>();
   // put keys and values in the Map      
   weakHashMap.put("1", "first");
   weakHashMap.put("2", "two");
   weakHashMap.put("3", "three");
   // printing the Map
   System.out.println("Map: "+weakHashMap);
   // returns a Set view of the Map
   Set set=weakHashMap.entrySet();
   // printing the set
   System.out.println("Set: "+set);
   // change Map value
   System.out.println("Changing map");
   weakHashMap.put("3", "new value");
   // print Map and set
   System.out.println("Changed Map: "+weakHashMap);
   System.out.println("Changed Set: "+set);

Let us compile and run the above program, this will produce the following result.

Map: {1=first, 2=two, 3=three}
Set: [1=first, 2=two, 3=three]
Changing map
Changed Map: {1=first, 2=two, 3=new value}
Changed Set: [1=first, 2=two, 3=new value]