HashMap isEmpty() Method in Java
Last Updated :
26 Nov, 2018
The java.util.HashMap.isEmpty() method of HashMap class is used to check for the emptiness of the map. The method returns True if no key-value pair or mapping is present in the map else False.
Syntax:
Hash_Map.isEmpty()
Parameters: The method does not take any parameters.
Return Value: The method returns boolean true if the map is empty or does not contain any mapping pairs else boolean false.
Below programs illustrates the working of java.util.HashMap.isEmpty() method:
Program 1: Mapping String Values to Integer Keys.
import java.util.*;
public class Hash_Map_Demo {
public static void main(String[] args)
{
HashMap<String, Integer> hash_map = new HashMap<String, Integer>();
hash_map.put( "Geeks" , 10 );
hash_map.put( "4" , 15 );
hash_map.put( "Geeks" , 20 );
hash_map.put( "Welcomes" , 25 );
hash_map.put( "You" , 30 );
System.out.println( "The Mappings are: " + hash_map);
System.out.println( "Is the map empty? " + hash_map.isEmpty());
}
}
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Output:
The Mappings are: {4=15, Geeks=20, You=30, Welcomes=25}
Is the map empty? false
Program 2: For an empty HashMap
import java.util.*;
public class Hash_Map_Demo {
public static void main(String[] args)
{
HashMap<String, Integer> hash_map = new HashMap<String, Integer>();
System.out.println( "The Mappings are: " + hash_map);
System.out.println( "Is the map empty? " + hash_map.isEmpty());
}
}
|
Output:
The Mappings are: {}
Is the map empty? true
Note: The same operation can be performed with any type of Mappings with variation and combination of different data types.
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