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Java IdentityHashMap put() Method with Example

IdentityHashMap Class put() method: Here, we are going to learn about the put() method of IdentityHashMap Class with its syntax and example.
Submitted by Preeti Jain, on March 06, 2020

IdentityHashMap Class put() method

• put() method is available in java.util package.
• put() method is used to set the given value element (val_ele) with the given key element (key_ele) when no value element associated previously with the given key otherwise it replaces the old value element with the given new value element (val_ele) for the given key element (key_ele) when any value element associated with the given key previously.
• put() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.
• put() method does not throw an exception at the time of replacing the value element if exists.

Syntax:

    public Value put(Key key_ele, Value val_ele);

Parameter(s):

• Key key_ele – represents the key element with which the given value is to be linked.
• Value val_ele – represents the value element to be linked with the given key element (key_ele).

Return value:

The return type of the method is Value, it returns the old value element linked with the given key element (key_ele) when exists otherwise it returns null.

Example:

// Java program to demonstrate the example 
// of Value put(Key key_ele, Value val_ele)
// method of IdentityHashMap 

import java.util.*;

public class PutOfIdentityHashMap {
    public static void main(String[] args) {
        // Instantiates a IdentityHashMap object
        Map < Integer, String > map = new IdentityHashMap < Integer, String > ();

        // By using put() method is to add
        // key-value pairs in a IdentityHashMap
        map.put(10, "C");
        map.put(20, "C++");
        map.put(50, "JAVA");
        map.put(40, "PHP");
        map.put(30, "SFDC");

        // Display IdentityHashMap
        System.out.println("IdentityHashMap: " + map);

        // By using put() method is to
        // replace the existing value associated
        // for the given key element with the
        // new value element

        map.put(50, "Microservices");

        // Display Modified IdentityHashMap
        System.out.print("IdentityHashMap: " + map);
    }
}

Output

IdentityHashMap: {20=C++, 40=PHP, 50=JAVA, 30=SFDC, 10=C}
IdentityHashMap: {20=C++, 40=PHP, 50=Microservices, 30=SFDC, 10=C}