Check key & Value existence in Hashtable example – Java

Example

In this example we are gonna see how to check Key and value existence in Hashtable. We will be using following two methods to perform this check:

containsKey(Object key): To check if the key present in Hashtable.
containsvalue(Object value): To check if the value present in Hashtable.

import java.util.Hashtable;

public class CheckKeyValueExample {
 
 public static void main(String[] args) {
 
   // Creating a Hashtable instance
   Hashtable<String, String> hashtable = new Hashtable<String, String>();
 
   // Adding key-value pairs to Hashtable
   hashtable.put("A", "Apple");
   hashtable.put("B", "Orange");
   hashtable.put("C", "Mango");
   hashtable.put("D", "Banana");
   hashtable.put("E", "Grapes");
 
   /* Checking Key existence using containsKey() method.
    * boolean containsKey(Object key) method returns true if the 
    * Hashtable contains the key, otherwise it returns false.
    */
   boolean keyFlag1 = hashtable.containsKey("A");
   System.out.println("Key A exists in Hashtable?: " + keyFlag1);
   boolean keyFlag2 = hashtable.containsKey("D");
   System.out.println("Key D exists in Hashtable?: " + keyFlag2);
   boolean keyFlag3 = hashtable.containsKey("G");
   System.out.println("Key G exists in Hashtable?: " + keyFlag3);
 
   /* Checking Value existence using containsValue() method.
    * boolean containsKey(Object key) method Returns true 
    * if this Hashtable maps one or more keys to this value..
    */
   boolean vFlag1 = hashtable.containsValue("Orange");
   System.out.println("Value Orange exists in Hashtable?: "+vFlag1);
   boolean vFlag2 = hashtable.containsValue("XYZ");
   System.out.println("Value XYZ exists in Hashtable?: "+vFlag2);
   boolean vFlag3 = hashtable.containsValue("Apple");
   System.out.println("Value Apple exists in Hashtable?: "+vFlag3);
 }
}

Output:

Key A exists in Hashtable?: true
Key D exists in Hashtable?: true
Key G exists in Hashtable?: false
Value Orange exists in Hashtable?: true
Value XYZ exists in Hashtable?: false
Value Apple exists in Hashtable?: true