WeakHashMap isEmpty() Method in Java with Examples
Last Updated :
19 Jul, 2018
The java.util.WeakHashMap.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:
Weak_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.WeakHashMap.isEmpty() method:
Program 1: Mapping String Values to Integer Keys.
import java.util.*;
public class Weak_Hash_Map_Demo {
public static void main(String[] args)
{
Map<String, Integer> weak_hash = new
WeakHashMap<String, Integer>();
weak_hash.put( "Geeks" , 10 );
weak_hash.put( "4" , 15 );
weak_hash.put( "Geeks" , 20 );
weak_hash.put( "Welcomes" , 25 );
weak_hash.put( "You" , 30 );
System.out.println( "The Mappings are: " +
weak_hash);
System.out.println( "Is the map empty? " +
weak_hash.isEmpty());
}
}
|
Output:
The Mappings are: {Welcomes=25, 4=15, You=30, Geeks=20}
Is the map empty? false
Program 2: For an empty WeakHashMap
import java.util.*;
public class Weak_Hash_Map_Demo {
public static void main(String[] args)
{
Map<String, Integer> weak_hash = new
WeakHashMap<String, Integer>();
System.out.println( "The Mappings are: " +
weak_hash);
System.out.println( "Is the map empty? " +
weak_hash.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.
All methods of Java.util.WeakHashmap Class
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