Map keySet() Method in Java with Examples

Map isEmpty() Method in Java with Examples

Last Updated : 02 Jan, 2019

This method is used to check if a map is having any entry for key and value pairs. If no mapping exists, then this returns true. Syntax:

boolean isEmpty()

Parameters: This method has no argument. Returns: This method returns True if the map does not contain any key-value mapping. Below programs show the implementation of int isEmpty() method. Program 1:

Java

// Java code to show the implementation of
// isEmpty method in Map interface
import java.util.*;
public class GfG {

    // Driver code
    public static void main(String[] args)
    {

        // Initializing a Map of type HashMap
        Map<String, String> map = new HashMap<>();

        System.out.println(map);

        System.out.println(map.isEmpty());
    }
}

Output:

{}
true

Program 2: Below is the code to show implementation of hashCode().

Java

// Java code to show the implementation of
// isEmpty method in Map interface
import java.util.*;
public class GfG {

    // Driver code
    public static void main(String[] args)
    {

        // Initializing a Map of type HashMap
        Map<String, String> map = new HashMap<>();
        map.put("1", "One");
        map.put("3", "Three");
        map.put("5", "Five");
        map.put("7", "Seven");
        map.put("9", "Ninde");
        System.out.println(map);

        System.out.println(map.isEmpty());
    }
}

Output:

{1=One, 3=Three, 5=Five, 7=Seven, 9=Ninde}
false

Reference: Oracle Docs

Map keySet() Method in Java with Examples

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