TreeSet contains() Method in Java

Difficulty Level : Basic
Last Updated : 26 Nov, 2018

The Java.util.TreeSet.contains() method is used to check if a specific element is present in the TreeSet or not. So basically it is used to check if a TreeSet contains any particular element.

Syntax:

Tree_Set.contains(Object element)

Parameters: The parameter element is of the type of TreeSet. This is the element that needs to be checked if it is present in the TreeSet or not.

Return Value: The method returns true if the element is present in the set else it return False.

Below program illustrate the Java.util.TreeSet.conatins() method:

// Java code to illustrate contains() method 
import java.io.*; 
import java.util.TreeSet; 
  
public class TreeSetDemo { 
    public static void main(String args[]) 
    { 
        // Creating an empty TreeSet 
        TreeSet<String> tree = new TreeSet<String>(); 
  
        // Use add() method to add elements into the Set 
        tree.add("Welcome"); 
        tree.add("To"); 
        tree.add("Geeks"); 
        tree.add("4"); 
        tree.add("Geeks"); 
        tree.add("TreeSet"); 
  
        // Displaying the TreeSet 
        System.out.println("TreeSet: " + tree); 
  
        // Check for "TreeSet" in the set 
        System.out.println("Does the Set contains 'TreeSet'? " +  
                                           tree.contains("TreeSet")); 
  
        // Check for "4" in the set 
        System.out.println("Does the Set contains '4'? " +  
                                             tree.contains("4")); 
  
        // Check if the list contains "No" 
        System.out.println("Does the Set contains 'No'? " +  
                                             tree.contains("No")); 
    } 
} 

Output:

TreeSet: [4, Geeks, To, TreeSet, Welcome]
Does the Set contains 'TreeSet'? true
Does the Set contains '4'? true
Does the Set contains 'No'? false

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