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Hashtable contains() Method in Java

Last Updated : 2 Jun, 2023

The java.util.Hashtable.contains(Object value) method in Java is used to check whether a particular value is being mapped by any keys present in the Hashtable. 

Syntax:

Hash_table.contains(Object value)

Parameters: The method accepts one parameter value of object type and refers to the value of the hashtable whose mapping is to be verified. 

Return Value: The method returns a boolean true value if the passed value is mapped by any of the keys in the Hashtable. Exceptions: The method throws NullPointerException if the passed value is Null. 

Below programs illustrate the working of the above-mentioned method: 

Program 1: 

Output:
Initial Table is: {10=Geeks, 20=Geeks, 30=You, 15=4, 25=Welcomes}
Is the value 'Geeks' present? true
Is the value 'World' present? false

Program 2: 

Output:
Initial Mappings are: {You=30, Welcomes=25, 4=15, Geeks=20}
Is the value '10' present? false
Is the value '30' present? true
Is the value '40' present? false
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