Skip to content
Related Articles

Related Articles

Hashtable clear() Method in Java
  • Last Updated : 28 Jun, 2018
GeeksforGeeks - Summer Carnival Banner

The java.util.Hashtable.clear() method in Java is used to clear and remove all of the keys from a specified Hashtable.

Syntax:

Hash_table.clear()

Parameters: The method does not accept any parameters.

Return Value: The method does not return any value.

Below programs are used to illustrate the working of java.util.Hashtable.clear() Method:
Program 1:






// Java code to illustrate the clear() method
import java.util.*;
  
public class Hash_Table_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty Hashtable
        Hashtable<Integer, String> hash_table = new Hashtable<Integer, String>();
  
        // Inserting Values into table
        hash_table.put(10, "Geeks");
        hash_table.put(15, "4");
        hash_table.put(20, "Geeks");
        hash_table.put(25, "Welcomes");
        hash_table.put(30, "You");
  
        // Displaying the Hashtable
        System.out.println("The Hashtable is: " + hash_table);
  
        // Clearing the hash table using clear()
        hash_table.clear();
  
        // Displaying the final Hashtable
        System.out.println("Finally the table looks like this: " + hash_table);
    }
}
Output:
The Hashtable is: {10=Geeks, 20=Geeks, 30=You, 15=4, 25=Welcomes}
Finally the table looks like this: {}

Program 2:




// Java code to illustrate the clear() method
import java.util.*;
  
public class Hash_Table_Demo {
    public static void main(String[] args)
    {
  
        // Creating an empty Hashtable
        Hashtable<String, Integer> hash_table = new Hashtable<String, Integer>();
  
        // Inserting Values into table
        hash_table.put("Geeks", 10);
        hash_table.put("4", 15);
        hash_table.put("Geeks", 20);
        hash_table.put("Welcomes", 25);
        hash_table.put("You", 30);
  
        // Displaying the Hashtable
        System.out.println("The Hashtable is: " + hash_table);
  
        // Clearing the hash table using clear()
        hash_table.clear();
  
        // Displaying the final Hashtable
        System.out.println("Finally the table looks like this: " + hash_table);
    }
}
Output:
The Hashtable is: {You=30, Welcomes=25, 4=15, Geeks=20}
Finally the table looks like this: {}

Note: The same operation can be performed with any type of variation and combination of different data types.

Attention reader! Don’t stop learning now. Get hold of all the important Java Foundation and Collections concepts with the Fundamentals of Java and Java Collections Course at a student-friendly price and become industry ready. To complete your preparation from learning a language to DS Algo and many more,  please refer Complete Interview Preparation Course.

My Personal Notes arrow_drop_up
Recommended Articles
Page :