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About Byron Kiourtzoglou

Byron Kiourtzoglou
Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.

Remove mapping from Hashtable example

In this example we shall show you how to remove mapping from a Hashtable, that means removing a key value pair from a Hashtable. To remove mapping from a Hashtable one should perform the following steps:

  • Create a new Hashtable.
  • Populate the hashtable with key value pairs, using put(K key, V value) API method of Hashtable.
  • Invoke the remove(Object key) API method of Hashtable, with a key as parameter. It removes a key and its corresponding value from the hashtable,

as described in the code snippet below.

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

public class RemoveMappingHashtable {
 
  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);

    /*

Object remove(Object key) operantion removes a key value pair from Hashtable. 

It returns either the value mapped with the key previously or null if no value was mapped.     
    */
    Object value = hashtable.remove("key_2");

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

Output:

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

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

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