Java Hashtable remove(Object key) Method Example

The remove(Object o) method will remove the mapping for the specified key from this hashtable if present.This method does nothing if the key is not in the hashtable.

Signature

public V remove(Object key)

This method removes the mapping for the specified key from this hashtable if present.Returns the value to which the key had been mapped in this hashtable, or null if the key did not have a mapping.

Example

The following example shows the usage of java.util.Hashtable.remove(key) method.

import java.util.Hashtable;
import java.util.Map;

public class RemoveMethodHashtableExample 
{
    public static void main(String args[])
    {
        // create an empty Hashtable
        Hashtable<Integer,String> hashtable1 = new Hashtable<Integer,String>();
        
        // use put() method to put elements to the Hashtable1
        hashtable1.put(1,"Element1");
        hashtable1.put(2,"Element2");
        hashtable1.put(3,"Element3");
        hashtable1.put(4,"Element4");
        hashtable1.put(5,"Element5");
        
        System.out.println("**Elements of hashtable1 before remove()**");
        
        //Print the elements of hashtable1
        for (Map.Entry<Integer,String> entry : hashtable1.entrySet())
        {
            System.out.println("Key : "+entry.getKey()+" Value : "+entry.getValue());
        }
        
        //lets remove the value associated to key "3"
        System.out.println("Element removed : \""+hashtable1.remove(3)+"\"");
        
        System.out.println("**Elements of hashtable1 after remove()**");
        //Print the elements of hashtable1
        for (Map.Entry<Integer,String> entry : hashtable1.entrySet())
        {
            System.out.println("Key : "+entry.getKey()+" Value : "+entry.getValue());
        }
    }
}

Output

**Elements of hashtable1 before remove()**
Key : 1 Value : Element1
Key : 2 Value : Element2
Key : 3 Value : Element3
Key : 4 Value : Element4
Key : 5 Value : Element5
Element removed : "Element3"
**Elements of hashtable1 after remove()**
Key : 1 Value : Element1
Key : 2 Value : Element2
Key : 4 Value : Element4
Key : 5 Value : Element5

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