With this example we are going to demonstrate how to check a key existence in a Hashtable. In short, to check if a key exists in 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
containsKey(Object key)API method of Hashtable, with a key as parameter. The method returns true if and only if the specified object is a key in this hashtable, as determined by the equals method and false otherwise.
Let’s take a look at the code snippet that follows:
package com.javacodegeeks.snippets.core;
import java.util.Hashtable;
public class CheckKeyHashtable {
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");
// boolean containsKey(Object key) returns true if the Hashtable contains the key, otherwise false.
boolean exists = hashtable.containsKey("key_2");
System.out.println("key_2 exists in Hashtable ? : " + exists);
}
}
Output:
key_2 exists in Hashtable ? : true
This was an example of how to check a key existence in a Hashtable in Java.
