A hash table is a collection of key-value pair. The isEmpty method of the Hashtable class is used to check if the specified Hashtable object is empty, i.e., it has no key-value entry present.
public boolean isEmpty()
This method doesn’t take any argument.
This method returns true if the Hashtable object doesn’t have any mappings. Otherwise, false will be returned.
The following example shows how to use the isEmpty method.
import java.util.Hashtable;class HashtableisEmptyExample {public static void main( String args[] ) {Hashtable<Integer, String> map = new Hashtable<>();System.out.println("The map is " + map);System.out.println("Checking if Hashtable is empty : "+ map.isEmpty());map.put(1, "one");map.put(2, "two");System.out.println("\nAfter Adding some mappings to the map is " + map);System.out.println("Checking if Hashtable is empty : "+ map.isEmpty());}}
In the code above:
In line 1, we imported the Hashtable class.
In line 4, we created a Hashtable object with the name map.
In line 6, we used the isEmpty method to check if the map is empty. true is returned as a result because the map object is empty.
In lines 7 and 8, we used the put method to add two mappings ({1=one, 2=two}) to the map object.
In line 10, we used the isEmpty method to check if the map is empty. false is returned as a result because the map object is not empty.