Home » Java programming language

Java WeakHashMap isEmpty() Method with Example

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

WeakHashMap Class isEmpty() method

• isEmpty() method is available in java.util package.
• isEmpty() method is used to check whether this map contains key-value pairs that exist in this map or not.
• isEmpty() 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.
• isEmpty() method does not throw an exception at the time of checking the empty status of this map.

Syntax:

    public boolean isEmpty();

Parameter(s):

• It does not accept any parameter.

Return value:

The return type of the method is boolean, it returns true when “none” key-value pairs exists otherwise it returns false.

Example:

// Java program to demonstrate the example 
// of boolean isEmpty() method of WeakHashMap 

import java.util.*;

public class IsEmptyOfWeakHashMap {
    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 isEmpty() method is to
        // check whether this WeakHashMap is
        // empty or not
        boolean status = map.isEmpty();

        //Display status
        System.out.print("map.isEmpty(): ");
        System.out.println(status);
    }
}

Output

WeakHashMap: {30=SFDC, 40=PHP, 10=C, 20=C++, 50=JAVA}
map.isEmpty(): false