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# Java - The Map.Entry Interface

The Map.Entry interface enables you to work with a map entry.

The entrySet( ) method declared by the Map interface returns a Set containing the map entries. Each of these set elements is a Map.Entry object.

Following table summarizes the methods declared by this interface.

SN | Methods with Description
--- | ---
1 | boolean equals(Object obj) Returns true if obj is a Map.Entry whose key and value are equal to that of the invoking object.
2 | Object getKey( ) Returns the key for this map entry.
3 | Object getValue( ) Returns the value for this map entry.
4 | int hashCode( ) Returns the hash code for this map entry.
5 | Object setValue(Object v) Sets the value for this map entry to v. A ClassCastException is thrown if v is not the correct type for the map. A NullPointerException is thrown if v is null and the map does not permit null keys. An UnsupportedOperationException is thrown if the map cannot be changed.

## Example:

Following is the example showing how Map.Entry can be used:

    import java.util.*;
    class HashMapDemo {
       public static void main(String args[]) {
          // Create a hash map
          HashMap hm = new HashMap();
          // Put elements to the map
          hm.put("Zara", new Double(3434.34));
          hm.put("Mahnaz", new Double(123.22));
          hm.put("Ayan", new Double(1378.00));
          hm.put("Daisy", new Double(99.22));
          hm.put("Qadir", new Double(-19.08));

          // Get a set of the entries
          Set set = hm.entrySet();
          // Get an iterator
          Iterator i = set.iterator();
          // Display elements
          while(i.hasNext()) {
             Map.Entry me = (Map.Entry)i.next();
             System.out.print(me.getKey() + ": ");
             System.out.println(me.getValue());
          }
          System.out.println();
          // Deposit 1000 into Zara's account
          double balance = ((Double)hm.get("Zara")).doubleValue();
          hm.put("Zara", new Double(balance + 1000));
          System.out.println("Zara's new balance: " +
          hm.get("Zara"));
       }
    }

This would produce following result:

    Daisy 99.22
    Qadir: -19.08
    Zara: 3434.34
    Ayan: 1378.0
    Mahnaz: 123.22
    Zara.s current balance: 4434.34

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