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Java WeakHashMap put() Method with Example

WeakHashMap Class put() method: Here, we are going to learn about the put() method of WeakHashMap Class with its syntax and example.
Submitted by Preeti Jain, on February 23, 2020

WeakHashMap Class put() method

• put() method is available in java.util package.
• put() method is used to maps the given value element (val_ele) with the given key element (key_ele) in this map when no value element (val_ele) exists for the given key element (key_ele) otherwise the old value element (val_ele) will be replaced by the new value element (val_ele).
• 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.

Syntax:

    public Object put(Object key_ele, Object val_ele);

Parameter(s):

• Object key_ele – represents the key element (key_ele) with which the given value element (val_ele) is to be mapped.
• Object val_ele – represents the value element (val_ele) to be mapped with the given key element (key_ele).

Return value:

The return type of the method is Object, it returns the old value element (val_ele) linked with the given key element (key_ele) otherwise it returns null when no value associated with the given key element (key-ele).

Example:

// Java program to demonstrate the example 
// of Object put(Object key_ele, Object val_ele)
// method of WeakHashMap 

import java.util.*;

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

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

        //Display WeakHashMap
        System.out.println("WeakHashMap: " + 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 WeakHashMap
        System.out.print("WeakHashMap: " + map);
    }
}

Output

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