The Java.util.HashSet.contains() method is used to check whether a specific element is present in the HashSet or not. So basically it is used to check if a Set contains any particular element.
Syntax:
Hash_Set.contains(Object element)
Parameters: The parameter element is of the type of HashSet. This is the element that needs to be tested if it is present in the set or not.
Return Value: The method returns true if the element is present in the set else return False.
Below program illustrate the Java.util.HashSet.contains() method:
// Java code to illustrate HashSet.contains() methodimport java.io.*;import java.util.HashSet;  public class HashSetDemo {    public static void main(String args[])    {        // Creating an empty HashSet        HashSet<String> set = new HashSet<String>();          // Using add() method to add elements into the Set        set.add("Welcome");        set.add("To");        set.add("Geeks");        set.add("4");        set.add("Geeks");          // Displaying the HashSet        System.out.println("HashSet: " + set);          // Check for "Geeks" in the set        System.out.println("Does the Set contains 'Geeks'? " + set.contains("Geeks"));          // Check for "4" in the set        System.out.println("Does the Set contains '4'? " + set.contains("4"));          // Check if the Set contains "No"        System.out.println("Does the Set contains 'No'? " + set.contains("No"));    }} |
Output:
HashSet: [4, Geeks, Welcome, To] Does the Set contains 'Geeks'? true Does the Set contains '4'? true Does the Set contains 'No'? false
