Java IdentityHashMap entrySet() Method

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Description

The Java IdentityHashMap entrySet() method is used to get a set view of the mappings contained in this map.

Declaration

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

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

Parameters

NA

Return Value

The method call returns a set view of the identity-mappings contained in this map.

Exception

NA

Getting Set of Entries from an IdentityHashMap of Integer, Integer Pair Example

The following example shows the usage of Java IdentityHashMap entrySet() method to get a Set view of a Map. We've created a Map object of Integer,Integer pairs. Then few entries are added, map is printed. Using entrySet() method, set is retrieved and printed.

package com.tutorialspoint;

import java.util.IdentityHashMap;

public class IdentityHashMapDemo {
   public static void main(String args[]) {
      
      // create identity map
      IdentityHashMap<Integer,Integer> newmap = new IdentityHashMap<>();

      // populate identity map
      newmap.put(1, 1);
      newmap.put(2, 2);
      newmap.put(3, 3); 

      System.out.println("Initial map elements: " + newmap);

      System.out.println("EntrySet view: " + newmap.entrySet());
   }    
}

Output

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

Initial map elements: {2=2, 3=3, 1=1}
EntrySet view: [2=2, 3=3, 1=1]

Getting Set of Entries from an IdentityHashMap of Integer, String Pair Example

The following example shows the usage of Java IdentityHashMap entrySet() method to get a Set view of a Map. We've created a Map object of Integer,String pairs. Then few entries are added, map is printed. Using entrySet() method, set is retrieved and printed.

package com.tutorialspoint;

import java.util.IdentityHashMap;

public class IdentityHashMapDemo {
   public static void main(String args[]) {
      
      // create identity map
      IdentityHashMap<Integer,String> newmap = new IdentityHashMap<>();

      // populate identity map
      newmap.put(1, "tutorials");
      newmap.put(2, "point");
      newmap.put(3, "is best"); 

      System.out.println("Initial map elements: " + newmap);

      System.out.println("EntrySet view: " + newmap.entrySet());
   }    
}

Output

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

Initial map elements: {2=point, 3=is best, 1=tutorials}
EntrySet view: [2=point, 3=is best, 1=tutorials]

Getting Set of Entries from an IdentityHashMap of Integer, Object Pair Example

The following example shows the usage of Java IdentityHashMap entrySet() method to get a Set view of a Map. We've created a Map object of Integer,Student pairs. Then few entries are added, map is printed. Using entrySet() method, set is retrieved and printed.

package com.tutorialspoint;

import java.util.IdentityHashMap;

public class IdentityHashMapDemo {
   public static void main(String args[]) {
      
      // create identity map
      IdentityHashMap<Integer,Student> newmap = new IdentityHashMap<>();

      // populate identity map
      newmap.put(1, new Student(1, "Julie"));
      newmap.put(2, new Student(2, "Robert"));
      newmap.put(3, new Student(3, "Adam"));

      System.out.println("Initial map elements: " + newmap);

      System.out.println("EntrySet view: " + newmap.entrySet());
   }    
}
class Student {
   int rollNo;
   String name;

   Student(int rollNo, String name){
      this.rollNo = rollNo;
      this.name = name;
   }

   @Override
   public String toString() {
      return "[ " + this.rollNo + ", " + this.name + " ]";
   }
}

Output

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

Initial map elements: {1=[ 1, Julie ], 3=[ 3, Adam ], 2=[ 2, Robert ]}
EntrySet view: [1=[ 1, Julie ], 3=[ 3, Adam ], 2=[ 2, Robert ]]