Hashtable

Remove all mappings from Hashtable example

With this example we are going to demonstrate how to remove all mappings from a Hashtable, that means removing all key value pairs from the Hashtable. In short, to remove all mappings from a Hashtable you should:

  • Create a new Hashtable.
  • Populate the hashtable with elements, using put(K key, V value) API method of Hashtable.
  • Invoke the clear() API method of Hashtable. It removes all keys and their corresponding values from the hashtable, so that the Hashtable contains no keys.

Let’s take a look at the code snippet that follows:

package com.javacodegeeks.snippets.core;
 
import java.util.Hashtable;

public class ClearHashtable {
 
  public static void main(String[] args) {
 
    // Create a Hashtable and populate it with elements
    Hashtable hashtable = new Hashtable();
    hashtable.put("key_1","value_1");
    hashtable.put("key_2","value_2");
    hashtable.put("key_3","value_3");
 
    System.out.println("Hashtable contains : " + hashtable);

    // void clear method() removes all mappings of Hashtable class
    hashtable.clear();

    System.out.println("Hashtable contains : " + hashtable);
  }
}

Output:

Hashtable contains : {key_3=value_3, key_2=value_2, key_1=value_1}
Hashtable contains : {}

 
This was an example of how to remove all mappings from a Hashtable in Java.

Ilias Tsagklis

Ilias is a software developer turned online entrepreneur. He is co-founder and Executive Editor at Java Code Geeks.
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