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Java Hashtable contains() Method with Example

Hashtable Class contains() method: Here, we are going to learn about the contains() method of Hashtable Class with its syntax and example.
Submitted by Preeti Jain, on February 17, 2020

Hashtable Class contains() method

• contains() method is available in java.util package.
• contains() method is used to check whether any keymap into the given value element (val_ele) or not.
• contains() method is a non-static method, it is accessible with the class object and if we try to access the method with the class name then we will get an error.
• contains() method may throw an exception at the time of checking the value element is mapped to any of the keys or not.
  NullPointerException: This exception may throw when the given parameter value is null exists.

Syntax:

    public boolean contains(Object val_ele);

Parameter(s):

• Object val_ele – represents the value element to be checked in this Hashtable.

Return value:

The return type of the method is boolean, it returns true when few key maps to the given value element (val_ele) otherwise it returns false.

Example:

// Java program is to demonstrate the example of
// contains() method of Hashtable

import java.util.*;

public class ContainsOfHashtable {
    public static void main(String[] args) {
        //Instantiate two hashtable object  
        Hashtable ht = new Hashtable();

        // By using put() method is to
        // add the linked values in an Hashtable
        ht.put(10, "C");
        ht.put(20, "C++");
        ht.put(30, "JAVA");
        ht.put(40, "PHP");
        ht.put(50, "SFDC");

        // Display Hashtable
        System.out.println("Hashtable: " + ht);

        // By using contains() method is to
        // check whether the given value element
        // exists in hashtable or not
        boolean status = ht.contains("JAVA");

        // Display Cloned Hashtable
        System.out.println("ht.contains(JAVA): " + status);
    }
}

Output

Hashtable: {10=C, 20=C++, 30=JAVA, 40=PHP, 50=SFDC}
ht.contains(JAVA): true