Hashtable clear() Method in Java (original) (raw)

Last Updated : 2 Jun, 2023

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 `

// 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 `

// 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.